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USUI HideyukiGraduate School of System Informatics / Department of System InformaticsProfessor
Research activity information
■ Award- Jul. 2018 37th JSST Annual International Conference on Simulation Technology, Student Poster Presentation Award, The Particle-In-Cell Simulation on LEO Spacecraft Charging and the Wake Structure using EMSESInternational society
- May 2017 International Conference on Computational Science 2017, International Conference on Computational Science 2017, Best poster award, Application of Block-structured Adaptive Mesh Refinement to Particle SimulationInternational society
- Oct. 2012 地球電磁気・地球惑星圏学会, 地球電磁気・地球惑星圏学会 田中舘賞, 計算機実験による宇宙機近傍のプラズマ電磁擾乱の研究Japan society
- Aug. 2000 International Symposium on Antennas and Propagation 2000, ISAP2000論文賞, Numerical Simulations of a three-wave coupling occurring in the ionospheric plasmaInternational society
- Dec. 1989 American Geophysical Union Fall meeting, Outstanding Student Paper Award, Computer Experiments of Shuttle Electrodynamic Tether SystemInternational society
- Mar. 2025, 遊・星・人, 34(1) (1), 27 - 42, Japanese将来の月周回・月面観測および開発における 帯電環境計測と評価に向けて[Refereed]Scientific journal
- Oct. 2024, arXiv:physics, 2410.05913, English, International magazine[Refereed]Research society
- Abstract To obtain both the intensities and phases of electric fields, it is necessary to calibrate the data observed by the sensor by consulting the sensor characteristics. The frequency profile of the sensor impedance obtained from the simulation is roughly consistent with that obtained from the theory. However, some differences are identified in the frequency profile of the sensor impedance obtained from the simulation compared to the theory. We conducted simulations using the particle-in-cell (PIC) simulation tool to analyze the impedance of electric field sensors immersed in magnetized space plasmas. The simulation model comprised a dipole sensor placed in a three-dimensional simulation box filled with electrons and ions. The dipole sensor was represented by perfect conductor rods. We carefully selected simulation parameters and employed an appropriate feeding technique to accurately evaluate the sensor impedance. We observed significant changes in the frequency dependence of the sensor impedance as cyclotron frequency varied. To understand the simulation results, we introduced the linear dispersion relation. By comparing the real part of the sensor impedance with the $$\omega-k$$ diagram, we found that the impedance peaks corresponded to frequencies at which branches of plasma waves were present, with $$k=k_{\text{half } }$$, representing half the wavelength equal to the tip-to-tip sensor length, i.e., the sensor can be assumed as the half-wavelength dipole antenna. Graphical AbstractSpringer Science and Business Media LLC, Mar. 2024, Earth, Planets and Space, 76(1) (1)[Refereed]Scientific journal
- We present a new model for current collected by a spherical Langmuir probe in magnetized plasmas. Data are obtained using state-of-the-art fully 3D kinetic particle-in-cell simulations. We perform a dimensional analysis and use it to determine the appropriate model function. The model is then empirically derived based on the simulation data for a range of probe potentials and magnetic field values with respect to the Debye length. The final model function is applicable to most space plasmas and can easily be generalized.AIP Publishing, Feb. 2024, Physics of Plasmas, 31(2) (2)[Refereed]Scientific journal
- Abstract In the tenuous atmospheric bodies of our solar system, space weathering on the celestial surface is an important process for its chemical and physical evolution and ambient environment on timescales of celestial evolution. Space plasma is a dominant energy and material source for space weathering. Plasma irradiation experiment in the laboratory is an effective method for modeling space weathering driven by space plasma. However, comprehensive modeling of plasma space weathering has not yet been conducted because the capabilities of the earlier facilities were not optimized for realistic space weathering; for example, the incident electron and ion were not irradiated in the same condition. Here, we developed a plasma irradiation system, Plasma Irradiation Emulator for Celestial Environments (PIECE) of the solar system bodies, which reproduces plasma space weathering in tenuous atmospheric bodies by the electron and ion irradiations in the same condition. We successfully developed a system with high electron and ion number fluxes of $$\sim 10^{13} - 10^{16} {\text{ particles cm } }^{ { - {2 } } } {\text{s } }^{ { - {1 } } }$$ at any acceleration energy in the range of 1–30 keV, which leads to a fluence of e.g., $$\sim 10^{18} - 10^{21} {\text{ particles cm } }^{ { - {2 } } } {\text{s } }^{ { - {1 } } }$$, with a 1-day irradiation time. This fluence corresponds to a plasma irradiation time of ~ 103–106 years on Europa. Graphical AbstractSpringer Science and Business Media LLC, Sep. 2023, Earth, Planets and Space, 75(1) (1)[Refereed]Scientific journal
- Abstract Due to the lack of a dense atmosphere, the Moon directly interacts with ambient plasmas and solar radiation, leading to lunar surface charging. Solar X‐rays drive the emission of photoelectrons and Auger electrons from the lunar surface to space. The Auger electrons have characteristic energies intrinsic to the photo‐emitting atoms and were recently identified at the Moon by Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun (ARTEMIS) observations. In this study, we developed a numerical model of the energy spectrum of lunar photoelectrons and Auger electrons, thereby comparing the predicted and observed energy spectra. By adjusting a scaling factor, the model well reproduces the ARTEMIS observations obtained in the solar wind, where the energy spectra are minimally affected by surface charging. Meanwhile, the energy spectra obtained in the geomagnetic tail can be significantly altered by lunar surface potentials. We show that it is difficult to determine a unique combination of the scaling factor and the lunar surface potential with the ARTEMIS energy resolution because of a strong parameter degeneracy. Nevertheless, for a fixed scaling factor, a strong correlation is identified between the lunar surface potentials inferred from the shifts of the energy spectra and those from the upward photoelectron beam energies, providing a proof of concept for the use of the photo‐emitted electrons as a new remote sensing tool of the lunar surface potential. We advocate for future observations of lunar electrons with a high energy resolution. This article is protected by copyright. All rights reserved.American Geophysical Union (AGU), Sep. 2023, Journal of Geophysical Research: Space Physics[Refereed]Scientific journal
- Abstract The Cassini spacecraft’s Grand Finale flybys through Saturn’s ionosphere provided unprecedented insight into the composition and dynamics of the gas giant’s upper atmosphere and a novel and complex spacecraft–plasma interaction. In this article, we further study Cassini’s interaction with Saturn’s ionosphere using three-dimensional particle-in-cell simulations. We focus on how electrons and ions, emitted from spacecraft surfaces due to the high-velocity impact of atmospheric water molecules, could have affected the spacecraft potential and low-energy plasma measurements. The simulations show emitted electrons extend upstream along the magnetic field, and for sufficiently high emission rates, charge the spacecraft to positive potentials. The lack of accurate emission rates and characteristics, however, makes differentiation between the prominence of secondary electron emission and ionospheric charged dust populations, which induce similar charging effects, difficult for Cassini. These results provide further context for Cassini’s final measurements and highlight the need for future laboratory studies to support high-velocity flyby missions through planetary and cometary ionospheres.American Astronomical Society, Jun. 2023, The Planetary Science Journal, 4(6) (6), 105 - 105[Refereed]Scientific journal
- International Union of Radio Science (URSI), Apr. 2023, URSI Radio Science Letters, 4, English[Refereed]Scientific journal
- American Geophysical Union (AGU), Jul. 2021, Geophysical Research Letters, 48(14) (14), English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Oxford University Press (OUP), Jun. 2021, Monthly Notices of the Royal Astronomical Society, 504(1) (1), 964 - 973, English, International magazine, Co-authored internationally
ABSTRACT A surprising and unexpected phenomenon observed during Cassini’s Grand Finale was the spacecraft charging to positive potentials in Saturn’s ionosphere. Here, the ionospheric plasma was depleted of free electrons with negatively charged ions and dust accumulating up to over 95 per cent of the negative charge density. To further understand the spacecraft–plasma interaction, we perform a three-dimensional Particle-In-Cell study of a model Cassini spacecraft immersed in plasma representative of Saturn’s ionosphere. The simulations reveal complex interaction features such as electron wings and a highly structured wake containing spacecraft-scale vortices. The results show how a large negative ion concentration combined with a large negative to positive ion mass ratio is able to drive the spacecraft to the observed positive potentials. Despite the high electron depletions, the electron properties are found as a significant controlling factor for the spacecraft potential together with the magnetic field orientation which induces a potential gradient directed across Cassini’s asymmetric body. This study reveals the global spacecraft interaction experienced by Cassini during the Grand Finale and how this is influenced by the unexpected negative ion and dust populations.[Refereed]Scientific journal - American Geophysical Union (AGU), Mar. 2021, Geophysical Research Letters, 48(5) (5), English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Elsevier BV, Feb. 2021, Planetary and Space Science, 198, 105176 - 105176, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Springer Science and Business Media LLC, Jun. 2020, Space Science Reviews, 216(4) (4), English, International magazine, Co-authored internationally[Refereed]Scientific journal
- 2020, Indonesian Journal of Geography, 52(1) (1), 98 - 104, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Lead, Institute of Electrical and Electronics Engineers (IEEE), Aug. 2019, IEEE transactins on Plasma Science, Vol. 47(Issue 8) (Issue 8), 3717 - 3723, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Mar. 2019, Journal of Advanced Simulation in Science and Engineering, 6, 21 - 31, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Mar. 2019, Physics of Plasmas, 26(3) (3), English, International magazine, Co-authored internationally[Refereed]Scientific journal
- 2019, Physics of Plasmas, 26(4) (4), 043701, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Dec. 2018, Proc. AGU Fall Meeting 2018, English[Refereed][Invited]International conference proceedings
- Springer Berlin Heidelberg, Dec. 2018, Earth, Planets and Space, 70(1) (1), English, International magazine, Co-authored internationally[Refereed]Scientific journal
- 神戸から配信する遠隔インタラクティブ講義「計算生命科学の基礎」の2017年度報告計算生命科学は,生命の理解に向けて,近年急速に進展している計算科学と医農工理学分野が融合した学際的研究領域である.様々な研究分野や産業界等への研究の拡がりが期待されており,包括的な基礎知識を習得する機会が求められている.神戸大学計算科学教育センターは,関係諸機関と協力して,遠隔インタラクティブ講義「計算生命科学の基礎」シリーズを2014年から全国に配信を開始し,昨年度は600名の受講登録を受け付けた.本稿では,2017年度に実施した「計算生命科学の基礎IV」と,最近注目されているAIやディープラーニングに焦点を当て特別編として実施したディープラーニングチュートリアルの開催結果について報告する.年々受講者が増え続けており,アンケートでも高評価を得ている..Nov. 2018, 大学ICT推進協議会2018年度年次大会論文集, 1 - 4, JapaneseSymposium
- Springer Singapore, Oct. 2018, Communications in Computer and Information Science, 255 - 268In book
- American Geophysical Union (AGU), Oct. 2018, Geophysical Research Letters, 45(19) (19), 10075 - 10083, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- The American Institute of Aeronautics and Astronautics, Sep. 2018, Journal of Propulsion and Power, 34(5) (5), 1109 - 1115, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- May 2018, Proceedings of the 15th Spacecraft Charging Technology Conference, 55th, EnglishPlasma particle simulation of ECR plasma generation in Air Breathing Ion Engine (ABIEInternational conference proceedings
- Blackwell Publishing Ltd, Feb. 2018, Journal of Geophysical Research: Space Physics, 123(2) (2), 1165 - 1177, English[Refereed]Scientific journal
- American Institute of Physics Inc., Jan. 2018, AIP Conference Proceedings, 1925, 020001, English[Refereed]International conference proceedings
- Jan. 2018, 第14回「宇宙環境シンポジウム」講演論文集, JAXA-SP-17-006, 125 - 129, Japanese極域飛翔体周辺のプラズマじょう乱に関する粒子シミュレーションSymposium
- Jan. 2018, 第14回「宇宙環境シンポジウム」講演論文集, JAXA-SP-17-006, 113 - 117, Japaneseプラズマ波動環境下における人工衛星帯電現象の数値モデリングSymposium
- Sep. 2017, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 122(9) (9), 9603 - 9621, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Feb. 2017, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 122(2) (2), 1555 - 1571, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- 2017, 大学ICT推進協議会2017年度年次大会論文集, TF1-2, 1 - 5, Japanese神戸から配信する遠隔インタラクティブ講義「計算生命科学の基礎」Symposium
- 2017, INTERNATIONAL CONFERENCE ON COMPUTATIONAL SCIENCE (ICCS 2017), 108, 2527 - 2536, English[Refereed]International conference proceedings
- Dec. 2016, RADIO SCIENCE, 51(12) (12), 1905 - 1922, English[Refereed][Invited]Scientific journal
- Aug. 2016, JOURNAL OF COMPUTATIONAL PHYSICS, 319, 231 - 241, English[Refereed]Scientific journal
- Jul. 2016, JOURNAL OF SPACECRAFT AND ROCKETS, 53(4) (4), 589 - 598, English[Refereed]Scientific journal
- 2016, Proceedings 2016 JSST International Conference on Simulation Technology, English[Refereed][Invited]International conference proceedings
- American Institute of Aeronautics and Astronautics Inc, AIAA, 2015, 53rd AIAA Aerospace Sciences Meeting, English[Refereed]International conference proceedings
- Dec. 2014, PHYSICS OF PLASMAS, 21(12) (12), English[Refereed]Scientific journal
- Jun. 2014, PHYSICS OF PLASMAS, 21(6) (6), English, International magazine, Co-authored internationally[Refereed]Scientific journal
- 2014, 2014 XXXITH URSI GENERAL ASSEMBLY AND SCIENTIFIC SYMPOSIUM (URSI GASS), EnglishStatistical Study and Particle Simulations about the Low Frequency Compornent of BEN observed by GEOTAIL Spacecraft[Refereed]International conference proceedings
- Jan. 2014, JOURNAL OF PROPULSION AND POWER, 30(1) (1), 233 - 245, English[Refereed]Scientific journal
- Jan. 2014, JOURNAL OF PROPULSION AND POWER, 30(1) (1), 186 - 196, English[Refereed]Scientific journal
- 2014, Plasma and Fusion Research, 9(SPECIALISSUE.1) (SPECIALISSUE.1), 2405008 - 2405008, English[Refereed]Scientific journal
- 2014, 2014 XXXITH URSI GENERAL ASSEMBLY AND SCIENTIFIC SYMPOSIUM (URSI GASS), EnglishFull Kinetic Simulation on Plasma Flow Response to a Meso-scale Magnetic Dipole[Refereed]International conference proceedings
- 2014, 2014 INTERNATIONAL CONFERENCE ON COMPUTATIONAL SCIENCE, 29, 2351 - 2359, English[Refereed]International conference proceedings
- Dec. 2013, ハイパフォーマンスコンピューティングと計算科学シンポジウム論文集, 2014, 40 - 40, JapaneseDevelopment of Adaptive Mesh Refinement Plasma PIC Simulation
- 大気吸入型イオンエンジン放電室内におけるプラズマ生成シミュレーションAbbreviatedJAXA, Dec. 2013, 第10回宇宙環境シンポジウム, JAXA-SP(JAXA-SP-13-016) (JAXA-SP-13-016), 61 - 64, JapaneseResearch institution
- Microwave Plasma Simulation for the Development of Air Breathing Ion EngineAbbreviatedAug. 2013, The 11th International School Symposium for Space Simulations, USB, EnglishInternational conference proceedings
- Microwave plasma simulation for the development of air breathing ion engineAbbreviatedJSASS, Jun. 2013, The 29th International Space Technology and Sciences, USB, EnglishInternational conference proceedings
- 日本航空宇宙学会, Jan. 2013, 宇宙科学技術連合講演会講演集, 57, 4p, JapaneseAnalysis of Satellite Charging Performance for Propellant less Orbital Contol Using the Charged SatelliteScientific journal
- A parallelized two-dimensional full particle-in-cell (PIC) simulations with an adaptive mesh refinement (AMR) technique for the interaction of solar wind with kinetic scale magnetosphere around a magnetic sail are conducted. For multi-scale simulations, the newly developed AMR-PIC code has a method to modify the grid size and time step interval of computational domain in the midst of the simulations temporally and locally. In the simulation results under the typical working condition introducing the AMR technique, it is shown that the direction of interplanetary magnetic field depend strongly on the magnetospheric configuration including electron dynamics and Alfven bow shock structure. Although more validation studies are needed, the AMR-PIC code shows the worth of development for multi-scale simulations.The Japan Society of Plasma Science and Nuclear Fusion Research, 2013, Plasma and Fusion Research, 8, 2406132 - 2406132, English[Refereed]Scientific journal
- 2013, 24TH IUPAP CONFERENCE ON COMPUTATIONAL PHYSICS (IUPAP-CCP 2012), 454(1) (1), English[Refereed]International conference proceedings
- 2013, Plasma and fusion research, 8, 2401149 - 2401149, English[Refereed]Scientific journal
- Blackwell Publishing Ltd, 2013, Journal of Geophysical Research: Space Physics, 118(9) (9), 5681 - 5694, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Oct. 2012, Computer Physics Communications, 183(10) (10), 2027 - 2034, English[Refereed]Scientific journal
- Oct. 2012, COMPUTER PHYSICS COMMUNICATIONS, 183(10) (10), 2027 - 2034, English[Refereed]Scientific journal
- Sep. 2012, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 117, English[Refereed]Scientific journal
- Solar wind plasma flow with interplanetary magnetic field (IMF) and the thrust of the magnetic sail are examined by time-dependent, two-dimensional, X-Y Cartesian, hybrid particle-in-cell (PIC) simulations. The hybrid-PIC simulation model is that the ions are treated kinetically as particles and the electrons are modeled as an inertia-less (mass-less) fluid. In this simulation, the real solar wind parameters around a near-earth orbit are used. The direction and strength of IMF are set to +Y direction which is perpendicular to the solar wind flow (+X direction) and 3 nT. Expressed in rL/L (the ratio of an ion Larmor radius rL of the solar wind at the magnetopause to a representative length of magnetic field L), when rL/L = 0.1 (in the case of MHD scale), magnetopause is formed accompanied by a fast magnetosonic bow shock. When rL/L = 2.0 (in the case of ion inertial scale), the electromagnetic interaction results in the formation of a magnetosphere with standing whistler waves. The drag coefficients, which is the thrust normalized by the solar wind inertial force, of both scales with IMF tend to increase compared with the cases without IMF because the incoming IMF accompanied by the solar wind piles up at upstream of the spacecraft. Also, on the ion inertial scale, the generation mechanism of Whistler wave and the influence of that on the thrust performance are revealed.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jun. 2012, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, 10(ists28) (ists28), Pb_43 - Pb_50, English[Refereed]Scientific journal
- May 2012, Proc. Intl. Conf. Simulation Technology, 262 - 267, EnglishDevelopment of a Scalable PIC Simulator and Its Application to Spacecraft-Plasma Interaction Problems[Refereed]International conference proceedings
- May 2012, JOURNAL OF PROPULSION AND POWER, 28(3) (3), 652 - 663, English[Refereed]Scientific journal
- Mar. 2012, PHYSICS OF PLASMAS, 19(3) (3), English[Refereed]Scientific journal
- Solar wind plasma behavior and thrust of a magnetic sail under the condition with interplanetary magnetic field (IMF) are examined by time-dependent, two-dimensional, X–Y Cartesian, hybrid particle-in-cell (PIC) simulations. Magnetic sail is a propellant less propulsion system proposed for an interplanetary space flight. The thrust force is produced by the interaction between magnetic dipole field artificially generated by superconducting coils in a spacecraft and a solar wind. In the present simulations, the ratio of ion Larmor radius at the magnetopause to characteristic length of the magnetosphere is set to 0.1, and IMF strength is set to 0 and 10nT. As simulation results, magnetic reconnection occurs due to superposition of IMF and dipole field in the solar wind flow field. The reconnection points depend on the direction of IMF and those have an important role in the formation of shock wave. When IMF is perpendicular to the solar wind flow direction, the thrust acting on the spacecraft increases compared to the case without IMF. When IMF is parallel to the solar wind flow direction, lift force is generated on the spacecraft. These phenomena are attributed to the difference in location of magnetic reconnection point depending on the direction of IMF.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2012, 日本航空宇宙学会論文集, 60(1) (1), 31 - 39, Japanese[Refereed]Scientific journal
- Japan Society for Simulation Technology, 2012, Proceedings of International Conference on Simulation Technology (JSST 2012), 587 - 589, EnglishParallelized Plasma Particle Simulation with Dynamic Domain Decomposition[Refereed]International conference proceedings
- 2012, Extended Abstract on the International Conference on Simulation Technology 2012, EnglishNumerical Simulation of Microwave Plasma in Air Breathing Ion Engine[Refereed]International conference proceedings
- Japan Society for Simulation Technology, 2012, Proceedings of International Conference on Simulation Technology (JSST 2012), 62 - 64, EnglishNumerical Simulation of Microwave Plasma in Air Breathing Ion Engine[Refereed]International conference proceedings
- Japan Society for Simulation Technology, 2012, Proceedings of International Conference on Simulation Technology (JSST 2012), 248 - 251, EnglishImplementation of AMR Technique into Parallelized Plasma Codes and Its Effectiveness[Refereed]International conference proceedings
- Japan Society for Simulation Technology, 2012, Proceedings of International Conference on Simulation Technology (JSST 2012), 583 - 586, EnglishFull PIC Simulation of Ion Beam Neutralization[Refereed]International conference proceedings
- Japan Society for Simulation Technology, 2012, Proceedings of International Conference on Simulation Technology (JSST 2012), 559 - 561, EnglishDevelopment of a Block-Structured AMR Module[Refereed]International conference proceedings
- Japan Society for Simulation Technology, 2012, Proceedings of International Conference on Simulation Technology (JSST 2012), 562 - 565, EnglishAMR-PIC Simulation on Solar Wind Interaction with Kinetic Scale Magnetosphere[Refereed]International conference proceedings
- Magnetic sail is a propellantless propulsion system used in space, which is capable of generating a propulsive force by the interaction between the magnetic field generated by a hoop coil and the solar wind plasma flow. Three dimensional hybrid (ion particles and electron fluid) particle-in-cell (PIC) simulation and scale-model experiment are performed to investigate the characteristics of the plasma flow around a magnetosphere on the ion inertial scale where an ion gyro radius rLi is comparable to the representative size of magnetosphere L. It is found that the dark region around magnetospheric boundary appearing in the experimental photograph corresponds to the region where the plasma density increases due to the plasma trapped by the magnetic field. The induced current which is both perpendicular to the plasma flow and the magnetic field also increases in the magnetospheric boundary region hence this region coincides with the magnetopause current layer. The width of the magnetopause current layer has a good agreement between the numerical simulation result and experimental result. Also, the predicted thrust value of 0.34 ± 0.01 N obtained by the hybrid simulation agrees well with the experimental result when numerical simulation is carried out by considering the ion-neutral collision effect. The hybrid PIC simulation carried out without considering the collisional effect gave a thrust value of 0.4 ± 0.01 N (increasing by a factor of 1.3), which can be applied to the thrust evaluation of the magnetic sail in a collisionless interplanetary space.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2012, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, 10(28) (28), Pb_51 - Pb_57, English[Refereed]Scientific journal
- Blackwell Publishing Ltd, 2012, Journal of Geophysical Research: Space Physics, 117(9) (9), English[Refereed]Scientific journal
- Aug. 2011, 電気学会研究会資料. FTE, 新エネルギー・環境研究会, 2011(9) (9), 71 - 76, JapaneseDevelopment of Electromagnetic Hybrid-PIC Plasma Simulation Code for Magneto-Plasma Sail
- Aug. 2011, TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 54(184) (184), 90 - 97, English[Refereed]Scientific journal
- May 2011, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 116, English[Refereed]Scientific journal
- 2011, 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011, English[Refereed]International conference proceedings
- 2011, PROCEEDINGS OF THE 19TH INTERNATIONAL EUROMICRO CONFERENCE ON PARALLEL, DISTRIBUTED, AND NETWORK-BASED PROCESSING, 277 - 281, English[Refereed]International conference proceedings
- Magnetic plasma sails have possibilities to reduce drastically mission durations of deep space explorations by using the momentum of the solar wind to produce its thrust. In order to produce a practical magnitude of the thrust, the magnetic plasma sails are required to inflate applied magnetic fields by injecting plasma from the spacecrafts. In this study, the magnetic field inflation by the plasma injection is numerically simulated by one component plasma model, which can be performed more robustly than those by hybrid simulations. The fundamental features of the injected plasma flow field and the electromagnetic field around the magnetic plasma sail are investigated, especially on the effects of the direction and the density of the plasma injection. The magnetic field can be inflated by the plasma injection in the one component plasma model. The direction and density of the plasma injection have strong impacts on the flow field and magnetic field inflation.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2011, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, Vol. 8, pp.Pb_109-Pb_114(27) (27), Pb_109 - Pb_114, English[Refereed]Scientific journal
- 2011, Plasma and Fusion Research, 6(1) (1), 2401101 - 2401101, English[Refereed]Scientific journal
- 2011, PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON COMPUTATIONAL SCIENCE (ICCS), 4, 2337 - 2343, English[Refereed]International conference proceedings
- Sep. 2010, IEEE TRANSACTIONS ON PLASMA SCIENCE, 38(9) (9), 2219 - 2228, English[Refereed]Scientific journal
- 2010, 61st International Astronautical Congress 2010, IAC 2010, 12, 10000 - 10009Numerical analysis of charged particle effects on solar sails for interplanetary flightInternational conference proceedings
- 2010, 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, AIAA-2010-6773, English[Refereed]International conference proceedings
- 2010, JAXA-RR-09-004,イオン加速グリッド耐久認定用数値解析ツールの研究開発ワークショップ論文集(宇宙航空研究開発機構), pp.32-37, Japaneseイオンエンジンにおけるビーム中和電子の粒子解析[Refereed]Scientific journal
- Jan. 2010, Advances in Geosciences: Volume 21: Solar Terrestrial (ST), 461 - 481, English[Refereed]In book
- 2010, Journal of Plasma and Fusion Research Series, Vol 9, pp. 586-591, EnglishDevelopment of Full Particle-In-Cell Simulation Code with Adaptive Mesh Refinement Technique[Refereed]Scientific journal
- Magnetic Sail is a propellantless propulsion system proposed for an interplanetary space flight. The propulsive force is produced by the interaction between the magnetic field artificially generated by a hoop coil equipped with the magnetic sail and the solar wind. Three-dimensional hybrid particle-in-cell simulations are performed to reproduce the plasma flow structure around the magnetic sail and to measure the propulsive force of the magnetic sail with two different coil currents. We report the characteristics of the magnetosphere, such as the profile of the magnetic field and the predicted thrust values obtained by simulations, which agree well with laboratory experiments, when simulations are carried out by considering the ion-neutral collision effect. The hybrid particle-in-cell simulation carried out without considering the collisional effect gave a thrust value of 2.3∼3.5 N, which can be applied to the thrust evaluation of the magnetic sail in a magnetosphere with size of 250∼300 km in a collisionless interplanetary space.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2010, Transaction of Japan Society for Aeronautical and Space Sciences Aerospace Technology Japan, Vol. 8, No. ists27, pp. Pb_19-(27) (27), Pb_19 - Pb_25, English[Refereed]Scientific journal
- Jan. 2010, JOURNAL OF PROPULSION AND POWER, 26(1) (1), 159 - 166, English[Refereed]Scientific journal
- The steady state of dipolar magnetic field expansion is examined by injecting a plasma jet from the center of the dipolar magnetic field (magnetic inflation). An effective magnetic inflation is essential for the realization of a magneto plasma sail (MPS), which produces a propulsive force by the interaction between the solar wind and an artificial dipolar magnetic field that is inflated by the plasma jet injected from the spacecraft. During the process of magnetic inflation, the finite Larmor radius effect is of practical significance since rL/LB is considerably greater than unity in a region far from the center of the dipolar magnetic field. The simulation result obtained using the ideal magnetohydrodynamics (MHD) model is overestimated, namely, it shows that the inflated magnetic field decays according to |B| ∝ r -2.0 since the magnetic field is frozen into the plasma jet. In comparison with the MHD result, the results obtained using the hybrid particle-in-cell code are more accurate. These results show that the inflated magnetic field decays according to |B| ∝ r -2.3 under the condition βin = 1 since the finite ion Larmor radius effect decreases the flow of magnetic flux with respect to the flow of plasma jet.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, Jul. 2009, JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 57(666) (666), 287 - 294, Japanese[Refereed]Scientific journal
- Jun. 2009, PHYSICS OF PLASMAS, 16(6) (6), 62904, English[Refereed]Scientific journal
- 2009, 47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace ExpositionInternational conference proceedings
- 2009, 2009 IEEE International Vacuum Electronics Conference, IVEC 2009, 383 - 384, English[Refereed]International conference proceedings
- 2009, RAREFIED GAS DYNAMICS, 1084, 784 - +, English[Refereed]International conference proceedings
- 2009, プラズマ核融合学会誌, Vol. 85, No.9, pp. 589-592, Japaneseマルチスケール粒子シミュレーション手法の開発と宇宙機‐宇宙プラズマ相互作用への応用[Refereed]Scientific journal
- 2009, ICS'09: PROCEEDINGS OF THE 2009 ACM SIGARCH INTERNATIONAL CONFERENCE ON SUPERCOMPUTING, 90 - 99, English[Refereed]International conference proceedings
- 2009, 14th International Congress on Plasma Physics 2008, Journal of Plasma and Fusion Research Series, vol 8, pp.1616-1621, EnglishNumerical Study of Inflation of a Dipolar Magnetic Field in Space by Plasma Jet Injection[Refereed]Scientific journal
- 2009, ADVANCES IN APPLIED PLASMA SCIENCE, Vol.7, pp. 103-106, EnglishNumerical Study of an Inflation of a Dipolar Magnetic Field by Plasma Jet Injection in Magneto Plasma Sail[Refereed]Scientific journal
- 2009, AIP Conference Proceedings, Vol. 1084, pp.784-792, EnglishNumerical Analysis of Magnetic Sail Spacecraft, 26th International Symposium on Rarefied Gas Dynamics[Refereed]Scientific journal
- 2009, Journal of Plasma and Fusion Research Series, Vol. 8, pp. 1569-1573, 1569 - 1573, EnglishMulti-Scale Plasma Particle Simulation for the Development of Interplanetary Flight System[Refereed]Scientific journal
- The Physical Society of Japan, 2009, Meeting Abstracts of the Physical Society of Japan, 64(0) (0), 255 - 255, Japanese[Refereed]Scientific journal
- A three-dimensional electrostatic full Particle-In-Cell code has been developed to analyze spacecraft-plasma interactions quantitatively. The code is expected to achieve highly accurate computation because it has no robust algorithm. We adopted the code to evaluate the electric field measurement onboard spacecraft, especially under low-density ambient plasma environment with photoelectron emission. In this paper, first, fundamental functions for computation of the electric field were validated in Low Earth Orbit and Geosynchronous Orbit environments by comparing with the thin-sheath limit theory and the thick-sheath limit theory, respectively. Second, the floating potential of a spacecraft model with photoelectron emission in Geosynchronous Orbit was computed to examine the effects of photoelectron emission to the electric potential around the spacecraft. The dependence of the floating potential on the photoelectron temperature was shown in the simulation.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2009, TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN, Vol. 7, No. ists26 pp.Pr_(26) (26), Pr_2_19 - Pr_2_24, English[Refereed]Scientific journal
- 2009, 14th International Congress on Plasma Physics 2008, Journal of Plasma and Fusion Research Series, vol 8, pp.1606-1610, EnglishEvaluation of Electric Field Measurement in Space Environment[Refereed]Scientific journal
- A full particle-in-cell (PIC) plasma simulator with higher accuracy as well as reasonable performance for studying spacecraft-plasma interactions has been developed. It is applied to estimate characteristics of the onboard current monitors (CRM) for a small scientific satellite REIMEI in the polar orbit, because calibration is required for the observation data. Basic characteristics in typical plasma environments including effects of the satellite geometry are demonstrated.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2009, JSASS On-Line Journal Space Technology Japan, Vol.7, No.ists26, pp.Pr_2_13-P(26) (26), Pr_2_13 - Pr_2_18, English[Refereed]Scientific journal
- A full particle-in-cell (PIC) plasma simulator with higher accuracy as well as reasonable performance for studying spacecraft-plasma interactions has been developed. It is applied to estimate characteristics of the onboard current monitors (CRM) for a small scientific satellite REIMEI in the polar orbit, because calibration is required for the observation data. Basic characteristics in typical plasma environments including effects of the satellite geometry are demonstrated.THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, 2009, TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN, Vol. 7, No. ists26, pp.Pr_2_13(26) (26), Pr_2_13 - Pr_2_18, English[Refereed]Scientific journal
- OpenMP Parallelization Method for Current Calculation in Plasma Particle Simulationプラズマ粒子シミュレーションで電磁界成分を更新する際には電流値が必要であり,そのために,個々の粒子の運動量を各空間格子点に集める必要がある.しかし,粒子が空間的にランダムに分布しているため,電流計算の並列演算による高速化は容易ではなく工夫を要する.本論文では,粒子の位置情報を利用して各スレッドに粒子を明示的に割り当てるスレッド並列化アルゴリズムを新しく提案し,OpenMPを用いた実装によりその有効性を検証した.動作検証により,提案手法のCPU台数効果はシミュレーション内の空間格子数の影響を受け,粒子数密度の影響はないことが分かった.特に,各スレッドに割り当てられた空間格子配列がキャッシュに収まりきる程度に細分化される場合,並列台数効果を得やすいことを明らかにした.特に並列台数10前後の場合,その台数効果はスーパリニアとなり,自動並列化コンパイラを用いた電流ルーチン実装に比べて高速になることを明らかにした.また,本提案手法は,各スレッドで全粒子を走査する冗長的な並列化方法であるため,従来アルゴリズムで用いられていた作業領域用配列は不要となり,シミュレーションに必要なメモリ容量を大幅に節約できることを示した.In Particle-In-Cell (PIC) plasma simulations, we calculate the current density to advance the electromagnetic fields. One of the ways to obtain the current density is to gather the velocity moment of each particle to the adjacent grid points. The current calculation is not basically parallelized because the particle positions, which are random in the simulation space, are independent of the array number of current density. In the present paper, we propose a new parallelization method which explicitly associates particles to threads by using OpenMP and evaluate the performance of the proposed method. We clarified that the scalability performance is affected by the number of spatial grid points and is independent of the number of particle per grid. In the proposed method, each thread is in charge of a part of the array of current density divided with the number of thread. When the memory size of the array allocated to each thread becomes small and close to the data cache size of CPU, we found that the scalability performance shows super-linear characteristics and the execution needs less time than the case of using the automatic parallelization compiler. In addition, each thread redundantly scans the particle array to obtain the information of the particle positions for assigning the corresponding particles in charge. Because of this redundant parallelization, we do not have to use work arrays and can save the memory consumed for simulations.情報処理学会, Aug. 2008, 情報処理学会論文誌. コンピューティングシステム, 1(2) (2), 250 - 260, Japanese[Refereed]
- Aug. 2008, RADIO SCIENCE, 43(4) (4), English[Refereed]Scientific journal
- May 2008, RADIO SCIENCE, 43(3) (3), English[Refereed]Scientific journal
- 2008, IEEE Transactions on Plasma Science, 36(5) (5), 2336 - 2349, English, International magazine, Co-authored internationally[Refereed]Scientific journal
- Vacuum Society of Japan, 2008, Journal of the Vacuum Society of Japan, 51(8) (8), 529 - 534, Japanese[Refereed]Scientific journal
- 2008, HIGH-PERFORMANCE COMPUTING, 4759, 383 - +, EnglishSpacecraft plasma environment analysis via large scale 3D plasma particle simulation[Refereed]International conference proceedings
- 2008, International Astronautical Federation - 59th International Astronautical Congress 2008, IAC 2008, 10, 6664 - 6670, EnglishThrust production mechanism of magnetic sail spacecraft with superconducting coils[Refereed]International conference proceedings
- 2007, Collection of Technical Papers - 45th AIAA Aerospace Sciences Meeting, 5, 3479 - 3486, EnglishEffect of photoelectrons on electric field antenna in spaceInternational conference proceedings
- 2007, Annual Report of the Earth Simulator Center, ISSN 1348-5830, 189-194Geospace Environment Simulator[Refereed]
- Oct. 2006, IEEE TRANSACTIONS ON PLASMA SCIENCE, 34(5) (5), 2094 - 2102, English[Refereed]Scientific journal
- Oct. 2006, IEEE TRANSACTIONS ON PLASMA SCIENCE, 34(5) (5), 2031 - 2037, English[Refereed]Scientific journal
- 2006, Proc. of 25th International Symposium on Space Technology and Science, 250-253Application of NuSPACE to the Spacecraft environment analysis[Refereed]
- Jun. 2005, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 110(A6) (A6), 1 - 6203, EnglishScientific journal
- Blackwell Publishing Ltd, 2005, Journal of Geophysical Research: Space Physics, 110(6) (6), English[Refereed]Scientific journal
- 2005, 9th Spacecraft Charging Technology Conference, JAXA Special Publication, ISSN 1349-113X, 600-603Development of Unstructured-grid EM particle Code for Spacecraft Environment Analysis[Refereed]
- 2005, Proceedings of ISSS-7, 71-74Development of Geospace Environment Simulation with Earth Simulator[Refereed]
- 2005, Sustainable Humanosphere, (1) (1), 15-, EnglishDevelopment of Geospace Environment Simulator (GES)[Refereed]
- Vectorized Particle Simulation Using "LISTVEC" Compile -directive on SX Super- computerPIC (Particle-In-Cell) method is frequently used for space plasma particle simulations. In this method, the field components (i.e. current, electric/magnetic field) are defined on grids and plasma particles are randomly distributed in space. To obtain the current, we need to calculate the velocity moment of the particles. The calculation is hard to perform on vector-type computers. Here, we introduce a new method where "LISTVEC" compile-directive on SX super-computer is used. We compare it with the conventional robust method.Information Processing Society of Japan (IPSJ), May 2004, 情報処理学会論文誌, 45(SIG6(ACS6)) (SIG6(ACS6)), 171 - 175, Japanese[Refereed]
- 日本航空宇宙学会, May 2004, Aeronautical and space sciences Japan, 52(604) (604), 126 - 134, JapaneseComputer Simulation Studies on Spacecraft Environment
- Vectorized Particle Simulation Using "LISTVEC" Compile -directive on SX Super- computerPIC (Particle-In-Cell) method is frequently used for space plasma particle simulations. In this method, the field components (i.e. current, electric/magnetic field) are defined on grids and plasma particles are randomly distributed in space. To obtain the current, we need to calculate the velocity moment of the particles. The calculation is hard to perform on vector-type computers. Here, we introduce a new method where "LISTVEC" compile-directive on SX super-computer is used. We compare it with the conventional robust method.Information Processing Society of Japan (IPSJ), 2004, Information Processing Society of Japan,, vol.45, No.sig6(acs 6), 171-17(6) (6), 171 - 175, Japanese
- 2004, SCIENTIFIC EXPLORATION, PLANETARY PROTECTION, ACTIVE EXPERIMENTS AND DUSTY PLASMAS, 34(11) (11), 2437 - 2440, EnglishScientific journal
- 2004, SCIENTIFIC EXPLORATION, PLANETARY PROTECTION, ACTIVE EXPERIMENTS AND DUSTY PLASMAS, 34(11) (11), 2441 - 2444, EnglishScientific journal
- 2004, SCIENTIFIC EXPLORATION, PLANETARY PROTECTION, ACTIVE EXPERIMENTS AND DUSTY PLASMAS, 34(11) (11), 2433 - 2436, EnglishScientific journal
- Oct. 2003, 日本航空宇宙学会誌 = Journal of the Japan Society for Aeronautical and Space Sciences, 51(597) (597), 249 - 250, JapaneseIntroduction to Review Series of Spacecraft and Space Plasma Environment
- 2003, PLASMA PHYSICS, 669, 735 - 738, EnglishTwo-dimensional particle simulation of electrostatic solitary waves with an open boundary condition[Refereed]International conference proceedings
- Dec. 2002, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 107(A12) (A12), 1 - 19, EnglishScientific journal
- A Problem Solving Environment for Space Plasma Computer SimulationsDue to development of super computers and high-speed network, roles of computer simulations are getting important. Plasma simulations have contributed a lot to the studies of space plasma, fusion plasma, and process plasma. However, simulation environments have not been friendly for researchers who don't program their own simulation codes. We herein propose a new PSE system for plasma simulation studies. This system is composed of WWW server, computational server, DB and DBMS server, visualization server, and other servers. The simulation codes are designed and implemented via object-oriented methodology. With help of the present system, space plasma simulations become more familiar with non-programming researchers, and even to general (non research) users.Information Processing Society of Japan (IPSJ), Sep. 2002, 情報処理学会論文誌, 43(SIG7(TOM6)) (SIG7(TOM6)), 105 - 117, Japanese[Refereed]
- An Object-oriented Plasma Particle Simulation Code Developed via Object Modeling Technique現在,プラズマ粒子シミュレーションは,プラズマ観測・応用の様々な分野において用いられている.本研究では,既存のコードをもとに,オブジェクト指向開発技法によりプラズマ粒子シミュレーションコードを設計した.設計したモデルは,プラズマ粒子コードの基本的な機能を有するスケルトンモデルである.オブジェクト指向分析設計方法論によるプラズマ粒子コードの設計については,これまで,詳しい報告がなかった.したがって本論文では,本設計をもとに独自のプラズマ粒子コードを設計できるよう,オブジェクトクラスの洗い出しからデザインまでを詳細に説明した.更に,このデザインに基づき,オブジェクト指向プラズマ粒子シミュレーションコードを,C++言語により実装した.実装コードの基本動作及びコードの再利用性を確認し,更に,既存の手続き型言語によるコードとの,処理速度の比較を行った.その結果,実装したオブジェクト指向コードは,Fortranによる既存コードと比較し,最大3倍程度の計算時間を必要とするが,高い再利用性を有することがわかった.The Institute of Electronics, Information and Communication Engineers, Aug. 2002, The Transactions of the Institute of Electronics,Information and Communication Engineers B, 85(8) (8), 1411 - 1425, Japanese[Refereed]
- Jan. 2002, 電気学会研究会資料. ED, 放電研究会, 2002(1) (1), 57 - 60JEM搭載アクティブプラズマ実験モジュールの検討と地上実験
- Jan. 2002, 電気学会研究会資料. ED, 放電研究会, 2002(1) (1), 53 - 56, JapaneseStudy of an active plasma experiment module for JEM and its associated computer experiments
- Blackwell Publishing Ltd, 2002, Journal of Geophysical Research: Space Physics, 107(12) (12), English[Refereed]Scientific journal
- Jan. 2002, NONLINEAR PROCESSES IN GEOPHYSICS, 9(1) (1), 1 - 10, English, International magazine, Co-authored internationallyNumerical simulations of a three-wave coupling occurring in the ionospheric plasmaScientific journal
- 宇宙プラズマ計算機シミュレーションの問題解決環境モデル宇宙プラズマシミュレーションは, スケール長が異なるコードが混在しており, マルチスケール計算の必要性が高まっている.また, コードやアルゴリズムが複雑で, 数値不安定性が生じやすい.コードの複雑さのため, 開発者以外は, コードを改良し, 共同開発を行うことが困難である.コード開発コストや時間を削減し, コードの生産性と利用環境を向上させるPSE環境が必要とされている.本稿では, モデル設定, パラメータテスト, 知識ベース, ジョブ管理, およびデータ可視化を備えたPSEを提案する.提案するPSEでは, WWWサーバーに, データベースを用いた知識ベースを組み込む.これにより, マルチスケール計算に対応し, 知識ベースを利用した数値安定性の予測が可能な環境を実現する.さらに, オブジェクト指向によってコードを開発・実装することにより, WWW上での初期パラメータおよびモデル設定が可能で, かつ, コードの改良が容易な環境を実現する.社団法人情報処理学会, Sep. 2001, 情報処理学会研究報告. MPS, 数理モデル化と問題解決研究報告, 2001(91) (91), 5 - 8
- Sep. 2001, IEICE TRANSACTIONS ON COMMUNICATIONS, E84B(9) (9), 2566 - 2573, English, International magazine, Co-authored internationallyComputer experiments on a three-wave coupling in association with microwave power transmission in space plasma[Refereed]Scientific journal
- Jul. 2001, IEICE TRANSACTIONS ON ELECTRONICS, E84C(7) (7), 967 - 972, EnglishAn object-oriented design of electromagnetic wave simulator for multi schemes
- Institute of Electronics, Information and Communication, Engineers, IEICE, 2001, IEICE Transactions on Electronics, E84-C(9) (9), 1279, EnglishErratum: (IEICE Transactions on Electronics E84-C:7 (967))Scientific journal
- 2001, PROCEEDINGS OF THE 7TH SPACECRAFT CHARGING TECHNOLOGY CONFERENCE, 476(476) (476), 535 - 538, EnglishPIC simulations of the space environment effects of plasma contactor[Refereed]International conference proceedings
- Jun. 2000, IEICE TRANSACTIONS ON ELECTRONICS, E83C(6) (6), 989 - 992, EnglishDevelopment of 1D object-oriented particle-in-cell code (1d-XOOPIC)
- 2000, 電子情報通学学会論文誌(英文), E83-C(6) (6), 989 - 9921次元オブジェクト指向型粒子シシュレーションコード(1d-XOOPIC)の開発
- Mar. 1999, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 104(A3) (A3), 4477 - 4484, English, International magazine, Co-authored internationallyScientific journal
- Elsevier Ltd, 1999, Advances in Space Research, 24(8) (8), 1069 - 1072, English[Refereed]Scientific journal
- Elsevier Ltd, 1999, Advances in Space Research, 24(1) (1), 99 - 102, English[Refereed]Scientific journal
- Computer Experiments on Measurement of Reentry Plasma Layer with Radio Waves宇宙往還機が大気圏に再突入する際, 機体前面に形成される高密度プラズマ層により通信途絶, すなわちブラックアウト現象が生じることが知られて久しい. このブラックアウト現象を理解し, かつその回避法の検討を行うには機体前面のプラズマ層の密度, 形状等のパラメータを定量的に把握する必要がある. その方法の一つに, 機体からの放射電波及び, プラズマ層からの反射電波の情報を用いるリモート計測が提唱されているが, この方法の検証は, これまでHYFLEXにリフレクトメータが搭載されたにとどまり, 本格的な検討はこれからの課題であると考えられる. 本論文では, 電磁粒子コードを用いた計算機実験により, 電波を用いたプラズマ層の計測法について定量的な検討を行う. 計算機実験では, モデル空間中の機体壁前面にプラズマ層を配置し, 機体面からそれに向けてDC成分を含まないパルスの電波を放射する. プラズマ層で反射された電波の強度及び位相情報を機体表面で取得し, その情報をもとにプラズマ層の密度に関するパラメータの推定を行う. 計算機実験の結果, 電波の位相情報を使うリフレクトメトリー法を用いることにより, 機体前面のプラズマ密度プロファイルが推定可能であることが示された. また, 反射波強度の周波数特性からプラズマ層の最高密度が計測可能であることも示された.The Institute of Electronics, Information and Communication Engineers, 1999, The Transactions of the Institute of Electronics,Information and Communication Engineers B, 82-B(1) (1), 81 - 87, Japanese
- Dec. 1997, GEOPHYSICAL RESEARCH LETTERS, 24(23) (23), 3049 - 3052, EnglishScientific journal
- Computer Experiments on Radio Blackout of a Reentry Vehicle and its Evasion with Magnetic Field Applied to the Reentry Plasma地球往還型宇宙機が地球大気圏に再突入する際に起こるブラックアウト現象に関する調査には, OREXやHYFLEX等の実際の再突入実験が実施されたが, このような宇宙実験は膨大な予算が必要となる. そこで, 我々はプラズマ電磁粒子コードを用いて, 計算機上でブラックアウト現象の再現およびその解析を行うことに成功した. また, ブラックアウト回避法として, 機体前面に生じる高密度プラズマ層に磁場をかける方法に着目し, その効果を調査する目的で計算機実験を行った. 今回は簡単のため, プラズマ層に印加する磁場を一様磁場とした. 計算機実験の結果, 機体からの通信電波が,高密度プラズマ層中ではホイスラモードおよびLモードで伝搬可能であることが確認された.The Institute of Electronics, Information and Communication Engineers, Mar. 1997, The Transactions of the Institute of Electronics,Information and Communication Engineers. B-(0xF9C2), 80(3) (3), 257 - 264, Japanese[Refereed]
- Jan. 1997, GEOPHYSICAL RESEARCH LETTERS, 24(1) (1), 49 - 52, EnglishIntense bursts of electron cyclotron harmonic waves near the dayside magnetopause observed by GEOTAIL[Refereed]Scientific journal
- 1997, RESULTS OF THE IASTP PROGRAM, 20(4-5) (4-5), 857 - 860, EnglishScientific journal
- American Geophysical Union, 1997, Geophysical Research Letters, 24(1) (1), 49 - 52, EnglishScientific journal
- Jun. 1994, PHYSICS OF PLASMAS, 1(6) (6), 1765 - 1767, English, International magazine, Co-authored internationally
- Feb. 1993, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 98(A2) (A2), 1531 - 1544, EnglishScientific journal
- May 1991, GEOPHYSICAL RESEARCH LETTERS, 18(5) (5), 821 - 824, EnglishScientific journal
- 2021, 地球電磁気・地球惑星圏学会総会及び講演会(Web), 150thThe future direction of SGEPSS: Subcommittee on the environment of airless bodies, moons, and spacecraft
- 2020, Space Science Reviews, 216(4) (4)Plasma Wave Investigation (PWI) Aboard BepiColombo Mio on the Trip to the First Measurement of Electric Fields, Electromagnetic Waves, and Radio Waves Around Mercury
- 2019, 宇宙科学技術連合講演会講演集(CD-ROM), 63rdFeasibility study of Air Breathing Ion Engine by using plasma numerical analysis in discharge chamber
- 2018, 日本表面真空学会学術講演会講演要旨集, 2018大気吸入型イオンエンジンにおけるECRプラズマ粒子シミュレーション
- 2017, 航空原動機・宇宙推進講演会講演論文集(CD-ROM), 57thCurrent status and future challenges of air breathing ion engine
- 2017, 宇宙科学技術連合講演会講演集(CD-ROM), 61st, ROMBUNNO.P26, JapaneseAdaptive Mesh Refinement Simulation on the Electromagnetic Environment around Ion Engine Plasma Beam
- 日本航空宇宙学会, 06 Sep. 2016, 宇宙科学技術連合講演会講演集, 60, 3p, JapaneseExperimental study on Air Breathing Ion Engine associate with the numerically calculated electromagnetic wave distribution in the discharge chamber
- 日本航空宇宙学会, 06 Sep. 2016, 宇宙科学技術連合講演会講演集, 60, 3p, JapaneseChallenges in use of Air Breathing Ion Engine in sub-low earth orbit environment
- 日本航空宇宙学会, 07 Oct. 2015, 宇宙科学技術連合講演会講演集, 59, 4p, JapaneseNumerical Simulation of Neutral Particle Distribution at the Reflector of Air Breathing Ion Engine
- 日本航空宇宙学会, 07 Oct. 2015, 宇宙科学技術連合講演会講演集, 59, 4p, JapanesePlasma analysis for developing the air breathing ion thruster by 3D PIC numerical simulation
- 日本計算工学会, Jun. 2015, 計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science, 20, 5p, JapaneseOptimization of Parallel Plasma Particle Simulations on MIC Architecture
- Analysis of Satellite Charging Using Charged Particle Beam Emission10th Spacecraft Environment Symposium (December 2-3, 2013, Science Museum), Tokyo JapanPhysical characteristics: Original contains color illustrationsJapan Aerospace Exploration Agency (JAXA), 31 Mar. 2014, 宇宙航空研究開発機構特別資料: 第10回宇宙環境シンポジウム講演論文集 = JAXA Special Publication: Proceedings of the 10th Spacecraft Environment Symposium, (13) (13), 43 - 46, Japanese
- The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69(1) (1), 253 - 253, Japanese28aAX-1 High-resolution Kinetic Simulation Method with Adaptive Mesh Refinement Technique
- 日本計算工学会, Jun. 2013, 計算工学講演会論文集 Proceedings of the Conference on Computational Engineering and Science, 18, 4p, JapaneseDynamic load balancing method for adaptive mesh refinement plasma particle simulation
- 08 Jan. 2013, ハイパフォーマンスコンピューティングと計算科学シンポジウム論文集, 2013, 67 - 67, Japanese適合格子細分化プラズマ粒子シミュレーションにおける動的負荷バランス手法の開発
- A Multi-Scale Electromagnetic Particle Code with Adaptive Mesh Refinement and Its ParallelizationSpace plasma phenomena occur in multi-scale processes from the electron scale to the magnetohydrodynamic scale. To investigate such multi-scale phenomena including plasma kinetic effects, we started to develop a new electromagnetic Particle-In-Cell (PIC) code with Adaptive Mesh Refinement (AMR) technique. AMR can realize high-resolution calculation saving computer resources by generating and removing hierarchical cells dynamically. In the parallelization, we adopt domain decomposition method and for good locality preserving and dynamical load balancing, we will use the Morton ordered curve. In the PIC method, particle calculation occupies most of the total calculation time. In our AMR-PIC code, time step intervals are also refined. To realize the load balancing between processes in the domain decomposition scheme, it is the most essential to consider the number of particle calculation loops for each cell among all hierarchical levels as a work weight for each processor. Therefore, we calculate the work weights based on the cost of particle calculation and hierarchical levels of each cell. Then we decompose the domain according to the Morton curve and the work weight, so that each processor has approximately the same amount of work. By performing a simple one-dimensional simulation, we confirmed that the dynamic load balancing is achieved and the computation time is reduced by introducing the dynamic domain decomposition scheme.The Institute of Electronics, Information and Communication Engineers, 14 Oct. 2011, IEICE technical report. Computer systems, 111(255) (255), 41 - 46, Japanese
- 応用物理学会, Jul. 2011, 日本計算工学会誌「計算工学」, Vol.16,No.3, pp. 2585-2589(7) (7), 602 - 605, Japanese惑星間航行システム開発に向けたマルチスケール粒子シミュレーション[Refereed]Introduction scientific journal
- Numerical simulation on plasma behavior and charging properties around solar sail7th Spacecraft Enivironment Symposium (October 19-20, 2010, Tokyo International Forum), Tokyo JapanPhysical characteristics: Original contains color illustrationsJapan Aerospace Exploration Agency (JAXA), 28 Feb. 2011, 宇宙航空研究開発機構特別資料: 第7回宇宙環境シンポジウム講演論文集 = JAXA Special Publication: Proceedings of the 7th Spacecraft Enivironment Symposium, (10) (10), 169 - 177, Japanese
- Electromagnetic Particle Simulation on Spacecraft-Plasma InteractionsSpacecraft charging occurs owing to the accumulation of incoming flux of space plasma to the spacecraft surface. In the worst case, spacecraft can suffer from total damage caused by discharge. Active plasma emission from a thruster for propulsion and attitude control as well as the potential difference in solar panels for the power supply also can influence the spacecraft plasma environment including the spacecraft itself. The influence will become an issue when we use the electric power and voltage much larger than those currently used for spacecraft system. However, it is almost impossible to evaluate the influence quantitatively by using a simple formulation. In such a situation, computer simulation using supercomputer becomes a power tool for the analysis of the interactions between spacecraft and space plasma. We will briefly introduce a simulation method using Particle-In-Cell model followed by some examples of simulation on spacecraft-plasma interactions such as spacecraft charging and plasma influence on electric antenna onboard satellite.The Institute of Electronics, Information and Communication Engineers, 17 Feb. 2011, IEICE technical report, 110(425) (425), 37 - 42, Japanese
- 日本計算工学会, 2011, 応用物理, 第80巻、第7号、p.0602-0605(3) (3), 2585 - 2589, Japanese惑星間航行システム開発に向けたマルチスケール粒子シミュレーション[Refereed]Introduction scientific journal
- Fundamental analysis of plasma behavior around a solar sail for interplanetary flight6th Spacecraft Enivironment Symposium (February 29-30, 2009. Kitakyushu International Conference Center)Physical characteristics: Original contains color illustrationsJapan Aerospace Exploration Agency (JAXA), 26 Feb. 2010, 宇宙航空研究開発機構特別資料: 第6回「宇宙環境シンポジウム」講演論文集 = JAXA Special Publication: Proceedings of the 6th Spacecraft Enivironment Symposium, (9) (9), Japanese
- An approach for high-resolution analysis of spacecraft-plasma interactions6th Spacecraft Enivironment Symposium (February 29-30, 2009. Kitakyushu International Conference Center)Physical characteristics: Original contains color illustrationsJapan Aerospace Exploration Agency (JAXA), 26 Feb. 2010, 宇宙航空研究開発機構特別資料: 第6回「宇宙環境シンポジウム」講演論文集 = JAXA Special Publication: Proceedings of the 6th Spacecraft Enivironment Symposium, (9) (9), 211 - 214, Japanese
- Numerical Analysis for Photoelectron Emission in the Magnetospheric PlasmaA three-dimensional electrostatic full Particle-In-Cell code has been developed to analyze spacecraft-plasma interactions quantitatively. We adopted the code to evaluate the correlation between the floating potential of a spacecraft and the photoelectron current in the magnetospheric plasma environment by comparing the computation results and the observation ones by the GEOTAIL spacecraft. The numerical model of the velocity distribution function of the photoelectron described as double Maxwellian was proposed to consider the correlation and the space charge effect of the photoelectron that affects to the current collection onto a spacecraft was also discussed.Japan Aerospace Exploration Agency, Feb. 2010, JAXA research and development report, 9, 11 - 18, Japanese
- Particle-In-Cell simulations on beam neutralizing electrons for ion engineIn order to examine the density and temperature distribution of electrons which neutralize ion beam emitted from an ion engine, we performed three-dimensional Particle-In-Cell simulations and investigated the electron behavior inside or outside the ion beam flows in the downstream region with respect to the accel grid. We calculated the charge density distribution of ions in three-dimensional spatial grid space covering the downstream region of the ion engine by using the ion beamlet data provided by Dr. Nakano. By solving Poisson's equation with the charge density data the potential distribution is calculated. Then we start emitting electrons from the down stream edge of the simulation region. At each time step, the charge density at each grid point is updated by the emitted electrons and the corresponding electric potential is renewed. By using the new potential values, we update the electrons dynamics by solving equation of motion for each electron. Since we focus on the short time scale of electron motion, we assume that ions which are about 100 thousand times heavier than electrons are immobile. We keep solving the above-mentioned PIC simulation until the steady state in terms of electron distribution is achieved. By using the electron data obtained in the simulations, we analyze the electron local temperature by calculating the local electron velocity distributions. From the data, we found that temperature is not uniform in space. The electron temperature at the ion beam edges become approximately 1.6 times higher than that of originally injected electronsJapan Aerospace Exploration Agency, Feb. 2010, JAXA research and development report, 9, 32 - 38, Japanese
- Sep. 2009, 第53回宇宙科学技術連合講演会・ 京都, Japanese“宇宙電磁環境計測に向けたアナログ回路部の小型集積化”
- Numerical analysis for measurement of photoelectron current in the magnetospheric plasmaA three-dimensional electrostatic full Particle-In-Cell code has been developed to analyze spacecraft-plasma interactions quantitatively. We adopted the code to evaluate the correlation between the floating potential of a spacecraft and the photoelectron current in the magnetospheric plasma environment by comparing the computation results and the observation ones by the GEOTAIL spacecraft. The numerical model of the velocity distribution function of the photoelectron was proposed to consider the correlation and the space charge effect of the photoelectron around a spacecraft was also discussed.Japan Aerospace Exploration Agency (JAXA), 31 Mar. 2009, 宇宙航空研究開発機構特別資料: 第5回「宇宙環境シンポジウム」講演論文集 = JAXA Special Publication: Proceeding of the 5th Spacecraft Environment Symposium, (8) (8), Japanese
- The Institute of Electronics, Information and Communication Engineers, 04 Mar. 2009, Proceedings of the IEICE General Conference, 2009(1) (1), 136 - 136, JapaneseC-2-97 Development of Practical Magnetoron simulator
- The Physical Society of Japan (JPS), 03 Mar. 2009, Meeting abstracts of the Physical Society of Japan, 64(1) (1), 193 - 193, Japanese27aSA-12 Development of multi-scale particle code for massively parallel computing
- Performance Evaluation of OhHelp'ed 3D Particle-in-Cell SimulationWe proposed an efficient and scalable load balancing method named OhHelp for Particle-in-Cell (PIC) simulations. This method simply and equally partitions the space domain, in which charged particles are distributed nonuniformly in general, so that each computation node works on each partitioned primary subdomain. Load imbalance problem caused by the nonuniformity of the particle distribution is solved by making every but one node also work on another subdomain where particles densely populate as its secondary subdomain together with a part of particles in it. We applied the OhHelp method to a production level full-3D PIC simulator for space plasma and evaluated its performance on our T2K Open Supercomputer. As a result, we confirmed our simulator is not only efficient showing 150-190 speedup with 256 CPU cores compared to the sequential execution of a reference simulator, but also scalable in terms of both the space domain size and the number of particles as the break down of execution times evidences.Information Processing Society of Japan (IPSJ), 19 Feb. 2009, IPSJ SIG Notes, 2009(14) (14), 1 - 6, Japanese
- 2009, RAREFIED GAS DYNAMICS, 1084, 895 - 900, EnglishParticle-In-Cell Simulation on the Characteristics of a Receiving Antenna in Space Plasma Environment[Refereed]
- 2009, 日本航空宇宙学会年会講演会講演集(CD-ROM), 40th, B09, Japanese3次元ハイブリッドコードを用いた磁気セイル地上実験の数値解析
- Kyoto University, Sep. 2008, Sustainable humanosphere : bulletin of Research Institute for Sustainable Humanosphere Kyoto University, 4, 11 - 11, EnglishParticle-In-Cell Simulation on the Characteristics of a Receiving Antenna in Space Plasma Environment(RECENT RESEARCH ACTIVITIES)
- The Physical Society of Japan (JPS), 25 Aug. 2008, Meeting abstracts of the Physical Society of Japan, 63(2) (2), 188 - 188, Japanese23aZH-6 Development of electromagnetic particle code with high efficiency and resolution using by adaptive mesh refinement
- Mar. 2008, RISH KDKシンポジウム, Japanese“磁気セイル宇宙機のMHD解析に向けて・”
- 2008, American Geophysical Union Fall meeting, San Fransisco, EnglishMonitor System for Space Electromagnetic Environments: Sensor Network in Space
- 2008, 26th International Symposium on Rarefied Gas Dynamics, 2008/7/21-25, Kyoto, 784-789, EnglishNumerical Simulation of Magnetic Sail Spacecraft with Superconducting Coils[Refereed]
- OhHelp: A Simple but Efficient Space-Partitioned Dynamic Load Balancing for Particle SimulationsThis paper proposes a new dynamic load balancing method for parallel particle simulations, named OhHelp, for the efficient execution on distributed memory systems. This method simply and equally partitions the space where charged particles reside, but effectively balances the loads, i.e., numbers of particles, among computation nodes each of which is assigned a partitioned subspace as its primarily responsible one. The load balancing is achieved by letting a node help another node which gives a part of its overflown load to the helper node. Therefore, the helper node is also responsible another subspace as its secondary one. The method makes the parallel simulation efficient not only because of the balanced number of particles, but also thanks to the balanced computational load for subspaces and the simple boundary data exchange between adjacent subspaces. In fact, our preliminary evaluation of an MPI implementation on the PrimePower HPC2500 supercomputer exhibits linear or super-linear speedup with up to 128 processors.Information Processing Society of Japan (IPSJ), 07 Dec. 2007, IPSJ SIG Notes, 2007(122) (122), 25 - 30, English
- Kyoto University, Aug. 2007, Sustainable humanosphere : bulletin of Research Institute for Sustainable Humanosphere Kyoto University, 3, 12 - 12, EnglishRelativistic Turning Acceleration of Resonant Electrons by Coherent Whistler-Mode Waves in a Dipole Magnetic Field(RECENT RESEARCH ACTIVITIES)
- May 2007, 日本地球惑星科学連合大会・ J250-011(口頭), Japanese“宇宙圏電磁環境モニターシステム(System for monitoring the electromagnetic environment in space)”
- Kyoto University, 31 Aug. 2006, Sustainable humanosphere : bulletin of Research Institute for Sustainable Humanosphere Kyoto University, 2, 12 - 12, EnglishNumerical Analysis on Microwave Beam Interaction with Ionospheric Plasma in Space Solar Power System(RECENT RESEARCH ACTIVITIES)
- 2006, 25th ISTS (International Symposium on Space Technology and Science), 2006/6/4-9, Kanazawa, 2006-b-23, EnglishGeospace environment simulator and the application to the analysis of plasma emission from ion propulsion engine[Refereed]
- 2006, 2006 IEEE INTERNATIONAL VACUUM ELECTRONICS CONFERENCE HELD JOINTLY WITH 2006 IEEE INTERNATIONAL VACUUM ELECTRON SOURCES, 347 - +, EnglishDevelopment of 3D electromagnetic PIC simulation code for magnetron[Refereed]
- 2006, 第3回宇宙環境シンポジウム・ 筑波, Japanese“宇宙電磁環境モニターシステム”
- 2005, RAST 2005: Proceedings of the 2nd International Conference on Recent Advances in Space Technologies, 2005, 34 - 38, English[Refereed]
- 2004, 2004 Asia-Pacific Radio Science Conference - Proceedings, 476-, EnglishStudy of spacecraft-plasma environment by unstructured-grid particle simulation[Refereed]
- 2004, 2004 Asia-Pacific Radio Science Conference - Proceedings, 588 - 591, EnglishParticle-In-Cell simulations on antenna characteristics in space plasma[Refereed]
- The Institute of Electronics, Information and Communication Engineers, 03 Mar. 2003, Proceedings of the IEICE General Conference, 2003(1) (1), 131 - 131, JapaneseStudy on the Numerical Modeling of Magnetron in Computer Experiments
- Sep. 2001, IEICE TRANSACTIONS ON ELECTRONICS, E84C(9) (9), 1279 - 1279, EnglishAn object-oriented design of electromagnetic wave simulator for multi schemes (vol E84-C, pg 967, 2001)Others
- The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2000, Proceedings of the IEICE General Conference, 2000(1) (1), 5 - 5, JapaneseDevelopment of an electromagnetic particle code with local fine grids
- The Institute of Electronics, Information and Communication Engineers, 07 Mar. 2000, Proceedings of the IEICE General Conference, 2000(1) (1), 32 - 32, JapaneseComputer Experiments and Theoretical Analysis on Magnetrons
- 2000, Proceedings of ISAP2000, 3, 21-25, EnglishAntenna analysis in magnetized plasma via particle-In-Cell simulations[Refereed]
- 2000, Proceedings of 6th Spacecraft Charging Technology Conference edited by David L. Cooke, 107-110, EnglishComputer experiments on radio blackout of a reentry vehicle[Refereed]
- 3-Dimensional Computer Experiments on Antenna Impedance in a Magnetized PlasmaWe studied antenna impedance in a magnetized plasma by performing 3 dimensional computer experiments with a PIC(particle In Cell)model. The previous studies are based on the assumptions such as infinitesimal dipole antenna and cold plasma.Contrary to these studies, we can deal with finite length of antenna and finite temperature of plasma in the analysis.In the experiments, we found variation of antenna impedance caused by the interaction with plasma waves, such as increase of impedance at the plasma frequency, shift of frequency resonance in hot plasma, and influence of impedance resonance due to electron cyclotron harmonic waves.The Institute of Electronics, Information and Communication Engineers, 09 Jul. 1998, IEICE technical report. Antennas and propagation, 98(169) (169), 57 - 60, Japanese
- The Institute of Electronics, Information and Communication Engineers, 06 Mar. 1998, Proceedings of the IEICE General Conference, 1998(1) (1), 25 - 25, JapaneseComputer Experiments on Plasma Measurements in the vicinity of a Reentry Vehicle by Radio Waves (2)
- The Institute of Electronics, Information and Communication Engineers, 06 Mar. 1998, Proceedings of the IEICE General Conference, 1998(1) (1), 26 - 26, JapaneseComputer Experiments on Antenna Impedance Measurements in Space Plasmas by Three-Dimensional Full Electromagnetic Particle Code
- Comuputer Experiments on measurement of a reentry plasma by radio wave宇宙往還機が大気圏に再突入する際, ブラックアウト現象(通信途絶)が起こることが知られて久しい. この現象の原因は機体表面において発生する強い衝撃波によって圧縮加熱された大気の電離により生じる高温高密度プラズマ層である. 従って, 機体周辺のプラズマ環境を把握することは通信系及び誘導系の最適設計を行うにあたって必要不可欠である. これまでプラズマパラメータの計測にはプローブが用いられてきたが高温環境を考えると材質の耐熱性などの問題がある. 本講演では電波を用いたプラズマパラメータのリモート計測手法を提唱し, 電磁粒子コードを用いた計算機実験を行った結果について報告する.The Institute of Electronics, Information and Communication Engineers, 06 Mar. 1997, Proceedings of the IEICE General Conference, 1997(1) (1), 169 - 169, Japanese
- Computer cxperiments on oscillating magnetronsマグネトロンの動作原理については20世紀初頭ごろからよく知られており, 既に成熟した技術として家電製品などにも使われるようになって久しいが, その製作にあたっては経験や実験の試行錯誤によるところが未だ多分にあるのが実状である。これはマグネトロンの動作における非線型的要素や回転電子極の不均質な構造の詳細な解析が困難であり, その動作の検証は実験に委ねざるを得ないからであるが, 実験の再現性や計測の正確性と自由度の観点から, このときに計算機実験を利用することは有用である。これまで既に幾つかの手法で計算機実験が行なわれてきている。The Institute of Electronics, Information and Communication Engineers, 06 Mar. 1997, Proceedings of the IEICE General Conference, 1997(1) (1), 12 - 12, Japanese
- 1997, The Fifth International School/Symposium for Space Simulations, 399-402, EnglishElectromagnetic Particle Simulations via Parallel Virtual Machines
- 1997, (20) (20), 857昼間側マグネトポーズで観測された電子サイクロトロン(]G0048[)調波の統計的研究
- Computer Experiments on the Measurement of the Thin Plasma Layer near a Reentry Spacecraft using Radio Wave Emission我々は電機粒子コード(KEMPO)を用いた計算機実験により、再突入宇宙機近値のブラックアウト時の電磁環境を解析している。再突入宇宙機が大気圏に再突入する時、宇宙機前方に発生する衝撃波により圧縮され高圧になった大気の一部は電離され、高密度プラズマの層ができる。ブラックアウトとは、このプラズマ層により、宇宙機から発信された電波が、反射、減衰され生じる、通信途絶現象のことである。再突入宇宙機の開発を行う上でブラックアウトの発生とその影響を予測することは通信系及び誘導系の最速設計を行う上で必要不可欠である。そのためには、まず再突入時に機体近傍に発生する高密度プラズマ層の状態を知ることが必要である。プローブを用いた直接計測は、シースの影響やプローブ自体の材質の問題等で困難である。そこで、我々は、宇宙機表面からの電波放射によって、再突入時に発生する高密度プラズマ層の様々なパラメータを測定する方法を開発することを考えた。The Institute of Electronics, Information and Communication Engineers, 27 Mar. 1995, Proceedings of the IEICE General Conference, 1995(1) (1), 115 - 115, Japanese
- 1993, 98(A2) (A2), 1531高電位テザー衛星に対するプラズマ応答
- 1991, 18(5) (5), 821 - 824電子ビーム放出とそれに関連するLHR波動励起:テザー系の計算機実験
- 1988, JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY, 40(8) (8), 949 - 961, English
■ Lectures, oral presentations, etc.
- 2024年度RISH電波科学計算機実験(KDK)シンポジウム, Mar. 2025, Japanese月面近傍におけるラングミュアプローブ特性の数値実験Oral presentation
- 2024年度RISH電波科学計算機実験(KDK)シンポジウム, Mar. 2025, Japanese水星磁気圏内部における太陽風イオンダイナミクスの3次元シミュレーション解析Oral presentation
- 2024年度RISH電波科学計算機実験(KDK)シンポジウム, Mar. 2025, Japanese上空-表層結合プラズマ計算手法に基づく月面帯電シミュレータの開発Oral presentation
- 第26回惑星圏シンポジウム(SPS2025, Mar. 2025, Japanese月面帯電環境の計測と評価[Invited]Invited oral presentation
- 17th Spacecraft Charging Technology Conference (SCTC), Jun. 2024, EnglishMicro-scale Electrostatic Structures formed on the Rough Surfaces of the MoonOral presentation
- Japan Geoscience Union Meeting, May 2024Hybrid particle simulation for ions dynamics in Mercury's inner Magnetosphere
- 地球電磁気・地球惑星圏学会第154回総会, Sep. 2023Statistical analysis of densities and temperatures of cold and hot electronsOral presentation
- 地球電磁気・地球惑星圏学会第154回総会, Sep. 2023Ion and magnetic field observations planned by Martian Moons eXploration (MMX)Oral presentation
- 地球電磁気・地球惑星圏学会第154回総会, Sep. 2023宇宙プラズマ中の低域混成 周波数付近におけるアンテナイン ピーダンス特性に関する粒子シ ミュレーションOral presentation
- URSI GASS 2023, Aug. 2023, English, Japan, International conferenceComputer Simulations on Single-Spacecraft Interferometry Technique Using MonopoleElectric Field Sensors
- URSI GASS 2023, Aug. 2023, International conferenceParticle Simulation on Antenna Characteristics at around the Lower-Hybrid Resonance Frequency in space plasma.Poster presentation
- URSI GASS 2023, Aug. 2023, International conferenceField perturbation and ion dynamics in the dayside Mercury's magnetospherePoster presentation
- URSI GASS 2023, Aug. 2023, International conferenceCassini’s floating potential in Titan’s ionosphere: 3-D Particle-In-Cell SimulationsPoster presentation
- Japan Geoscience Union Meeting 2023, May 2023Computer simulations on measurements of space potentials on the Earth's moon surface
- Japan Geoscience Union Meeting 2023, May 2023昼側月面におけるオージェ電子分光の実現可能性の研究
- Japan Geoscience Union Meeting 2023, May 2023低域混成周波数帯のアンテナインピーダンス共鳴特性に関 する数値シミュレーション
- Japan Geoscience Union Meeting 2023, May 2023彗星高密度プラズマの表面じょう乱に関する粒子シミュレ ーション
- Japan Geoscience Union Meeting 2023, May 2023Particle-In-Cell Simulations of Interferometry. Observations by Single Spacecraft
- STEシミュレーション研究会, Mar. 2023磁気圏環境変動を考慮した人工衛星帯電解析手法の開発Oral presentation
- STEシミュレーション研究会, Mar. 2023低温プラズマで被覆された金属物体の電波散乱特性の数値シミュレーションOral presentation
- 第24回惑星圏研究会(SPS2023), Feb. 2023粒子シミュレーションによる水星磁気圏イオンダイナ ミクス解析Poster presentation
- 第 23 回 宇宙科学シンポジウム, Jan. 2023月面利用の拡大に向けた超小型・高機能な宇宙放射線環境の計測技術構築の基礎研究
- プラズマ科学のフロンティア 2022 研究会, Dec. 2022スパコンで紐解く月惑星環境[Invited]
- 地球電磁気・地球惑星圏学会152回総会, Nov. 2022月面利用に向けた超小型・高機能な宇宙放射線 環境の計測技術構築の基礎研究Poster presentation
- 地球電磁気・地球惑星圏学会152回総会, Nov. 2022Particle Simulations on Characteristics of Electric Field Sensors applied to the Interferometry technique in Space PlasmasPoster presentation
- 地球電磁気・地球惑星圏学会152回総会, Nov. 2022月面からの光電子とオージェ電子放出モデル の開発
- 地球電磁気・地球惑星圏学会152回総会, Nov. 2022水星磁気圏昼間側擾乱に関する粒子シミュレー ションPoster presentation
- 2022 URSI-Japan Radio Science Meeting, Sep. 2022, English, Korakuen Campus, Chuo University, Japan, International conferenceSimulation Study on Characteristics of Electric Field Sensors applied to the Interferometry technique in Space PlasmasPoster presentation
- 2022 URSI-Japan Radio Science Meeting, Sep. 2022, English, Korakuen Campus, Chuo University, Japan, International conferenceAnalysis of Radio Wave Scattering by Metal Objects Covered by PlasmaPoster presentation
- 2022 URSI-Japan Radio Science Meeting, Sep. 2022, English, Korakuen Campus, Chuo University, Japan, International conferenceParticle Simulations on Antenna Characteristics in Space Plasma near the Lower-Hybrid Resonance FrequencyPoster presentation
- 日本地球惑星科学連合2022年大会, May 2022, Japanese地球磁気圏尾部での月面から放出されるAuger電子と光電子ビームの特性Oral presentation
- 日本地球惑星科学連合2022年大会, May 2022, 幕張メッセ, JapanComputer Simulation on Antenna Impedance of Electric Field Sensors in Magnetized Plasmas.Oral presentation
- 日本地球惑星科学連合2022年大会, May 2022, 幕張メッセ, Japan宇宙プラズマ中の低周波域アンテナ特性に関する粒子シミュレーションOral presentation
- 2022年RISH電波科学計算機実験シンポジウム, Mar. 2022宇宙プラズマ中における電界センサー特性に関する計算機シミュレーション
- 2022年RISH電波科学計算機実験シンポジウム, Mar. 2022粒子シミュレーションによる微粒子後方プラズマウェイクの構造解析
- 第23回惑星圏研究会, Feb. 2022ARTEMIS による昼側月面から放出される Auger 電 子と光電子ビームの観測Poster presentation
- 地球電磁気・地球惑星圏学会第150回総会, Nov. 2021Study on Electric Field Sensor Impedance in Magnetized Plasma by PIC SimulationOral presentation
- 地球電磁気・地球惑星圏学会第150回総会, Nov. 2021太陽風プラズマによる月面帯 電現象の表面形状への依存性Oral presentation
- 地球電磁気・地球惑星圏学会第150回総会, Nov. 2021The future direction of SGEPSS: Subcommittee on the environment of airless bodiesmoonsand spacecraftOral presentation
- 地球電磁気・地球惑星圏学会第150回総会, Nov. 2021太陽系天体の宇宙風化再現実 験に向けた汎用プラズマ照射装置 の開発・評価の現状Oral presentation
- 地球電磁気・地球惑星圏学会第150回総会, Nov. 2021ARTEMISによる昼側月面から 放出されるAuger電子と光電子ビー ムの観測Oral presentation
- ⽇本地球惑星科学連合2021年⼤会, Jun. 2021Future formation-flight mission FACTORS: Development of plasma particle instruments and evaluation of electric field measurements with short electric field sensorsPoster presentation
- ⽇本地球惑星科学連合2021年⼤会, Jun. 2021Study on Electric Field Sensor Impedance in Magnetized Plasma by PIC Simulation.Oral presentation
- ⽇本地球惑星科学連合2021年⼤会, Jun. 2021フォボス夜側表⾯帯電過程の2次元粒⼦シミュレーションOral presentation
- ⽇本地球惑星科学連合2021年⼤会, Jun. 2021荷電粒⼦層に覆われた物体の電波散乱特性に関する数値シミュレーションPoster presentation
- ⽇本地球惑星科学連合2021年⼤会, Jun. 2021⽉⾯空洞の表⾯帯電特性に関するプラズマ粒⼦シミュレーションOral presentation
- ⽇本地球惑星科学連合2021年⼤会, Jun. 2021⽔星磁気圏昼間側マグネトポーズに関するハイブリッド粒子シュミレーションPoster presentation
- STEシミュレーション研究会・KDKシンポジウム 合同研究会, Mar. 2021宇宙デブリの電波散乱特性に関するプラズマ粒子シミュレーション
- STEシミュレーション研究会・KDKシンポジウム 合同研究会, Mar. 2021科学衛星に搭載する電界センサーの特性評価に関する計算機シミュレーション
- 第22回惑星圏研究会, Feb. 2021, Japanese月環境学の創成Oral presentation
- 第22回惑星圏研究会, Feb. 2021, EnglishThe Surface Charging Processes of Airless PlanetaryOral presentation
- 第22回惑星圏研究会, Feb. 2021, Japanese水星磁気圏境界面の太陽風依存性に関するハイブリッド粒子シ ミュレーションPoster presentation
- SGEPSS Fall Meeting 2020, Nov. 2020, EnglishElectric Field Sensor Impedance in Magnetized Plasma by Particle-inCell SimulationOral presentation
- SGEPSS Fall Meeting 2020, Nov. 2020, EnglishFull PIC simulations of the surface charging on the nightside of Phobos: The effect of surface-plasma interactionOral presentation
- SGEPSS Fall Meeting 2020, Nov. 2020, Japanese宇宙環境の時間変動を考慮し た人工衛星帯電数値解析手法の開 発Oral presentation
- SGEPSS Fall Meeting 2020, Nov. 2020, Japaneseあらせ衛星で観測された孤立 静電ポテンシャル構造の解析Oral presentation
- JpGU-AGU Joint Meeting 2020, Jul. 2020, JapaneseReview report of Japanese Participation in Artemis Program from The Views of Science and EngineeringOral presentation
- JpGU-AGU Joint Meeting 2020, Jul. 2020, EnglishDesign of electric field measurements in the future mission FACTORS targeting transverse ion acceleration in the terrestrial polar magnetospherePoster presentation
- JpGU-AGU Joint Meeting 2020, Jul. 2020, JapaneseFull PIC simulations of the surface charging on the night side of PhobosOral presentation
- JpGU-AGU Joint Meeting 2020, Jul. 2020, EnglishDevelopment of Generic Plasma Irradiation System for Modeling of Space Weathering at Solar System BodiesPoster presentation
- JpGU-AGU Joint Meeting 2020, Jul. 2020, EnglishComputer Simulation of Electric Field Sensor in Space PlasmaOral presentation
- JpGU-AGU Joint Meeting 2020, Jul. 2020, Japaneseアルテミス計画参画に向けた月のプラズマ・ダスト環境に関する検討Oral presentation
- Symposium on Planetary Sciences 2020, Feb. 2020, English, 仙台BepiColombo SHOTS Project: A Comparative Study of Mercury's Magnetosphere Using MHD and Hybrid Particle SimulationsPoster presentation
- Symposium on Planetary Sciences 2020, Feb. 2020Development of Generic Plasma Irradiation System for Modeling of Space Weathering at Solar System BodiesPoster presentation
- Symposium on Planetary Sciences 2020, Feb. 20202-D Particle-In-Cell Calculations of Non-Neutral Plasma Structure near the Phobos Plasma Wake Region and Its Effect on the Surface ChargingPoster presentation
- 惑星圏研究会2020, Feb. 2020水探査を含めた国際宇宙探査,理学からの期待
- Symposium on Planetary Sciences2020, Feb. 2020, EnglishRecent Activities of Solid Body-Plasma Interaction SimulationsPoster presentation
- The 4th PSTEP International Symposium, Jan. 2020Modeling of Spacecraft Charging Processes in Time-varying Space Environment
- AGU Fall Meeting2019, Dec. 2019, English, San Francisco, International conferenceElectron cyclotron harmonic waves observed by the Arase satellite: identification of their wavelengths and phase speedsPoster presentation
- AGU Fall Meeting 2019, Dec. 2019, English, San Francisco, International conferenceA collaborative study of the Hermean magnetosphere using the multiple numerical and visualization techniques of the SHOTS projectPoster presentation
- AGU Fall Meeting 2019, Dec. 2019, English, San Francisco, International conferenceParticle-in-Cell Simulation on the Electron Dynamics at the Dayside Magnetopause in a Small MagnetospherePoster presentation
- TACT2019, Nov. 2019, English, International conferenceNumerical simulation of charged particle in cathodic arc plasmaPoster presentation
- 第16回宇宙環境シンポジウム, Nov. 2019, Japanese, 東京都市大学横浜キャンパス, Domestic conference大気吸入型イオンエンジンにおけるプラズマ数値解析による成立性の検討Oral presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, Japanese, 熊本(熊本市国際交流会館), Domestic conferenceあらせ衛星と線形解析による電子サイクロ トロン高調波とその発生環境に関する考察Oral presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, 熊本(熊本市国際交流会館), Domestic conferenceCorrelations of low-energy electrons with chorus emissions observed by ERG: An event studyOral presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, 熊本(熊本市国際交流会館), Domestic conferenceあらせ衛星によって観測された孤立静電ポテン シャル構造Poster presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, 熊本(熊本市国際交流会館), Domestic conferenceExtremely collimated electron beams observed by the ERG satellitePoster presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, Japanese, 熊本(熊本市国際交流会館), Domestic conference太陽風と火星起源イオンのフォボス表面への 衝突の数値実験Poster presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, Japanese, 熊本(熊本市国際交流会館), Domestic conference電子反射法を用いた太陽風中での月面磁場強度 推定Poster presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, Japanese, 熊本(熊本市国際交流会館), Domestic conference太陽系天体の宇宙風化再現実験に向けた汎用 プラズマ照射装置の開発Poster presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, 熊本(熊本市国際交流会館), Domestic conferenceSHOTS simulations of Mercury's magnetosphere for the BepiColombo missionPoster presentation
- Society of Geomagnetism and Earth, Planetary and Space Sciences, Oct. 2019, Japanese, 熊本(熊本市国際交流会館), Domestic conference衛星帯電緩和ビームによるプローブ電場計測干 渉に関する粒子シミュレーションPoster presentation
- 16th Asia Oceania Geosciences Society, Jul. 2019, English, Singapore, International conferenceParticleincell Simulation Study on the Dayside Magnetopause in a Smallscale MagnetosphereInvited oral presentation
- 平成29年度RISH電波科学計算機実験シンポジウム, Mar. 2019, Japanese, Uji, Domestic conference弱磁場天体と太陽風の相互作用に関する全粒子シミュレーションPoster presentation
- Symposium on Planetary Science 2019, Feb. 2019, English, Sendai, International conferenceNumerical simulation on plasma dynamics at the dayside magnetopause in a small-scale magnetospherePoster presentation
- 第144回 地球電磁気・地球惑星圏学会 総会・講演会, Nov. 2018, Japanese, Nagoya, Domestic conference電子反射法を用いた太陽風中での月面磁場強度推定Poster presentation
- 第144回 地球電磁気・地球惑星圏学会 総会・講演会, Nov. 2018, Japanese, Nagoya, Domestic conference探査衛星あらせのデータを用いた突発性電子サイクロトロン高調波の解析Poster presentation
- 第15回宇宙環境シンポジウム, Nov. 2018, Japanese, Sendai, Domestic conference大気吸入型イオンエンジン放電室内におけるECRプラズマ生成のPIC法を用いた数値解析Oral presentation
- 第15回宇宙環境シンポジウム, Nov. 2018, Japanese, Sendai, Domestic conference帯電緩和ビーム搭載科学衛星近傍の静電環境に関する粒子シミュレーションOral presentation
- 第144回 地球電磁気・地球惑星圏学会 総会・講演会, Nov. 2018, Japanese, Nagoya, Domestic conference小型磁気圏昼間側マグネトポーズでの電子ダイナミクスに関する全粒子シミュレーションOral presentation
- 第15回宇宙環境シンポジウム, Nov. 2018, Japanese, Sendai, Domestic conferenceテスト粒子シミュレーションによる月面磁気異常上空でのプラズマ速度分布関数解析Oral presentation
- 第144回 地球電磁気・地球惑星圏学会 総会・講演会, Nov. 2018, Japanese, Nagoya, Domestic conferenceDensity depletions associated with enhancements of ECH emissions observed by ERGOral presentation
- 第144回 地球電磁気・地球惑星圏学会 総会・講演会, Nov. 2018, Japanese, Nagoya, Domestic conference1次元静電ブラソフシミュレーションを用いた電離圏観測ロケットウェイク近傍の電子速度分布関数に関する考察Poster presentation
- 18th Asia Simulation Conference, Oct. 2018, English, Kyoto, International conferenceParticle in Cell Simulation to Study the Charging and Evolution of Wake Structure of LEO SpacecraftOral presentation
- The 13th International School and Symposium on Space Simulations (ISSS-13), Sep. 2018, English, Los Angeles, International conferenceThree-Dimensional Particle-In-Cell Simulations on Plasma Disturbance Near a Low-Earth Orbit SpacecraftPoster presentation
- the 37th JSST Annual International Conference on Simulation Technology, Sep. 2018, English, Hokkaidou, International conferenceThe Particle-In- Cell simulation on LEO spacecraft charging and the wake structure using EMSESOral presentation
- The 13th International School and Symposium on Space Simulations (ISSS-13), Sep. 2018, English, Los Angeles, International conferencePlasma Particle Simulation of ECR Plasma Generation in Air Breathing Ion Engine (ABIE)Poster presentation
- The 13th International School and Symposium on Space Simulations (ISSS-13), Sep. 2018, English, Los Angeles, International conferenceParticle Simulation Analysis of Spacecraft Charging Processes in Plasma Wave EnvironmentPoster presentation
- The 13th International School and Symposium on Space Simulations (ISSS-13), Sep. 2018, English, Los Angeles, International conference3D PIC Simulation on the Plasma Dynamics in a Small-Scale MagnetospherePoster presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceWake Formation behind Small SatellitesPoster presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceSpacecraft Charging Study in Japan[Invited]Invited oral presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferencePlasma Particle Simulation of ECR Plasma Generation in Air Breathing Ion Engine (ABIE)Poster presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceParticle Simulation on the Electromagnetic Environment of Ion Thruster Beam NeutralizationPoster presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceParticle Simulation Analysis of Spacecraft Charging Processes in Plasma Wave EnvironmentPoster presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceNumerical Study on the Plasma Disturbance an Charging Processes by Booms of an Ionospheric RocketPoster presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceNumerical Study on Plasma Disturbance near a Low-Earth Orbit SatellitePoster presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceNumerical Simulation of Spacecraft Charging Processes in Time-varying Plasma Environment[Invited]Invited oral presentation
- the 15th Spaccraft Charging Technology Conference (SCTC), Jun. 2018, English, Kobe, International conferenceThe Impact of Auroral Electron Streams on LEO Polar Satellites as a Source of ChargingPoster presentation
- JPGU, May 2018, Japanese, Chiba, Domestic conference弱磁場天体の小型磁気圏形成に関する全粒子シミュレーションPoster presentation
- JPGU, May 2018, Japanese, Chiba, Domestic conferenceSimulation study of the dependence of the whistler-mode chorus generation on properties of energetic electrons in the Earth's inner magnetospherePoster presentation
- 2nd URSI AT-RASC, May 2018, English, Gran Canaria, International conferenceNumerical Simulation of Spacecraft Charging Processes in Time-varying Plasma EnvironmentOral presentation
- 平成29年度RISH電波科学計算機実験シンポジウム, Mar. 2018, Japanese, Uji, Domestic conference小型天体・宇宙プラズマ相互作用過程の粒子シミュレーションOral presentation
- 平成29年度RISH電波科学計算機実験シンポジウム, Mar. 2018, Japanese, Uji, Domestic conference弱磁場天体と太陽風の相互作用に関する全粒子シミュレーションPoster presentation
- 平成29年度RISH電波科学計算機実験シンポジウム, Mar. 2018, Japanese, Uji, Domestic conference宇宙機推進用イオンビームの電磁環境に関する格子多階層型粒子シミュレーションPoster presentation
- 第19回惑星圏研究会, Feb. 2018, Japanese, Sendai, Domestic conference弱磁場天体と太陽風の相互作用に関する全粒子シミュレーションPoster presentation
- 第19回惑星圏研究会, Feb. 2018, Japanese, Sendai, Domestic conference宇宙プラズマ・小型固体天体相互作用の粒子シミュレーションPoster presentation
- PSTEP研究集会「太陽地球圏環境予測のためのモデル研究の展望」第2回, Feb. 2018, Japanese, Domestic conferenceプラズマ環境時間変動を考慮した衛星帯電モデリングに関する考察Poster presentation
- 第4回兵庫県立大学計算科学連携センター学術会議「シミュレーションを支える基盤研究」, Nov. 2017, Japanese, Kobe, Domestic conference小型天体環境に関するプラズマ粒子シミュレーションInvited oral presentation
- 第14回宇宙環境シンポジウム, Nov. 2017, Japanese, Kobe, Domestic conference極域電離圏飛翔体周辺のプラズマじょう乱に関する粒子シミュレーションOral presentation
- 第14回宇宙環境シンポジウム, Nov. 2017, Japanese, Kobe, Domestic conferenceプラズマ波動電界環境下における人工衛星帯電現象の数値モデリングOral presentation
- 第142回 地球電磁気・地球惑星圏学会 総会・講演会, Oct. 2017, Japanese, Uji, Domestic conference小型磁気圏形成とそのダイポール磁場強度依存性に関する考察Oral presentation
- 第142回 地球電磁気・地球惑星圏学会 総会・講演会, Oct. 2017, Japanese, Uji, Domestic conference弱磁場天体の小型磁気圏形成に関する全粒子シミュレーションPoster presentation
- 第61回宇宙科学技術連合講演会, Oct. 2017, Japanese, Niigata, Domestic conference宇宙機推進用イオンビームの電荷中和条件に関する粒子シミュレーションPoster presentation
- 第61回宇宙科学技術連合講演会, Oct. 2017, Japanese, Niigata, Domestic conferenceイオンエンジンプラズマ粒子ビーム電磁環境に関する適合格子細分化シミュレーションPoster presentation
- Japan-Norway project leaders seminar, Oct. 2017, English, Tokyo, International conferenceJapan-Norway Partnership in space science simulations[Invited]Invited oral presentation
- STEシミュレーション研究会, Sep. 2017, Japanese, Kobe, Domestic conference弱磁場天体の小型磁気圏形成に関する全粒子シミュレーションOral presentation
- ポスト「京」萌芽的課題・計算惑星 アプリケーション開発状況共有ワークショップ, Aug. 2017, Japanese, Domestic conference地球磁気圏・衛星環境の超並列シミュレーションに向けた高性能プラズマ計算コードの開発Oral presentation
- URSI Genenral Assembly and Scientific Symposium, Aug. 2017, English, Montreal, International conferenceNumerical Modeling of Spacecraft Potential Modulations due to Time-Varying Plasma Wave FieldsOral presentation
- 名古屋大学HPC 計算科学連携研究プロジェクト成果報告シンポジウム, Jun. 2017, Japanese, Domestic conference小型天体・太陽風プラズマ相互作用過程の超並列粒子シミュレーションOral presentation
- JPGU, May 2017, Japanese, Chiba, Domestic conference重イオン放出弱磁場小型天体のプラズマ環境に関する粒子シミュレーションPoster presentation
- JPGU, May 2017, Japanese, Chiba, Domestic conference極域電離圏飛翔体周辺のプラズマじょう乱に関する粒子シミュレーションPoster presentation
- JPGU, May 2017, Japanese, Chiba, Domestic conferenceプラズマ波動電界による人工衛星電位変動現象の数値モデリングPoster presentation
- 8th International Conference on the Physics of Dusty Plasmas (ICPDP), May 2017, English, Prague, International conferenceParticle Simulations of Electric and Dust Environment Near the Lunar Vertical HolePoster presentation
- International Conference on Computational Science (ICCS) 2017, May 2017, English, Zurich, International conferenceApplication of Block-structured Adaptive Mesh Refinement to Particle simulationPoster presentation
- Birkeland 150 year Anniversary Symposium “The Heritage of Kristian Birkeland”, Apr. 2017, English, Tokyo, International conferenceEducation without borders: how to achieve the best synergy in Japanese-Norwegian academic projects[Invited]Invited oral presentation
- 第64回応用物理学会春季学術講演会, Mar. 2017, Japanese, Yokohama, Domestic conference磁場印加型イオン成膜装置内部の荷電粒子ダイナミクスに関するシミュレーションOral presentation
- 平成28年度RISH電波科学計算機実験シンポジウム, Mar. 2017, Japanese, Uji, Domestic conferenceプラズマ波動電界存在下での衛星電位変動の数値モデリングPoster presentation
- 平成28年度RISH電波科学計算機実験シンポジウム, Mar. 2017, Japanese, Uji, Domestic conferenceイオンビームの工学利用に関する粒子シミュレーションPoster presentation
- PSTEP研究集会「太陽地球圏環境予測のためのモデル研究の展望」, Jan. 2017, Japanese, Domestic conferenceプラズマ波動存在下での衛星近傍プラズマ環境変動の数値モデリングPoster presentation
- 第332回生存圏シンポジウム宇宙プラズマ波動研究会, Dec. 2016, Japanese, Uji, Domestic conferenceプラズマシミュレーション援用による大気吸入型イオンエンジンの実験的研究Poster presentation
- American Geophysical Union (AGU) Fall meeting, Dec. 2016, English, SanFrancisco, International conferenceElectron current in the boundary layer of a mini-magnetosphere above a lunar magnetic anomalyPoster presentation
- 第140回 地球電磁気・地球惑星圏学会 総会・講演会, Nov. 2016, Japanese, Hakata, Domestic conference月面磁気異常上空のミニ磁気圏境界層における電子電流Oral presentation
- 第140回地球電磁気・地球惑星圏学会 総会・講演会, Nov. 2016, Japanese, Domestic conferenceプラズマ波動交番電界中 の衛星電位変動現象の 数値モデリングOral presentation
- 第13回宇宙環境シンポジウム, Nov. 2016, English, Musashi-koganei, Domestic conferenceDiagnozing LEO satellite anomalies using NOAA 15 electron data in association with geomagnetic perturbationsOral presentation
- 一般向けスパコンセミナー「未来へ続くスパコンの挑戦、シミュレーションが変える私たちの暮らし」, Oct. 2016, Japanese, Kobe, Domestic conferenceスパコンが解き明かす人類生存環境としての宇宙[Invited]Invited oral presentation
- 第60回宇宙科学技術連合講演会, Sep. 2016, Japanese, Hakodate, Domestic conference放電室内電界分布の計算結果を考慮した大気吸入型イオンエンジンの実験的研究Oral presentation
- 第60回宇宙科学技術連合講演会, Sep. 2016, Japanese, Hakodate, Domestic conference超低軌道領域における大気吸入型イオンエンジンの利用と課題Oral presentation
- STEシミュレーション研究会, Sep. 2016, Japanese, Domestic conferencePIC modeling of spacecraft-plasma interaction effects on double-probe electric field measurementsOral presentation
- Japan-Norway Arctic Science & Innovation Week 2016, Jun. 2016, English, Tokyo, Domestic conferenceInvolving students in research – success factors and challenges[Invited]Invited oral presentation
- JPGU, May 2016, Japanese, Chiba, Domestic conference磁気異常上空の小型磁気圏境界における電子ダイナミクスに関する粒子シミュレーション解析Oral presentation
- IEEE AP-S kansai Chapter, May 2016, Japanese, Kobe, Domestic conferenceスーパーコンピュータで宇宙を拓くInvited oral presentation
- 九州大学先端的計算科学研究プロジェクト 平成27年度成果報告会, Apr. 2016, Japanese, Domestic conference月周辺プラズマ環境の高並列プラズマ粒子シミュレーションOral presentation
- 第63回応用物理学会春季学術講演会, Mar. 2016, Japanese, Tokyo, Domestic conference分子流入を考慮した大気吸入型イオンエンジンの中性粒子シミュレーションOral presentation
- 平成27年度RISH電波科学計算機実験シンポジウム, Mar. 2016, Japanese, Uji, Domestic conference人工衛星搭載イオンエンジン中和器の地上実験に関するプラズマ数値シミュレーションPoster presentation
- 平成27年度RISH電波科学計算機実験シンポジウム, Mar. 2016, Japanese, Uji, Domestic conferenceメニーコアプロセッサ向け高効率プラズマ粒子計算手法の研究Oral presentation
- 平成27年度RISH電波科学計算機実験シンポジウム, Mar. 2016, Japanese, Uji, Domestic conferenceブロック型適合格子細分化法を用いたマルチグリッド法ポアソンソルバーの開発Poster presentation
- 平成27年度RISH電波科学計算機実験シンポジウム, Mar. 2016, Japanese, Uji, Domestic conferenceブロック型適合格子細分化法フレームワークのSugarscape シミュレーションへの応用Oral presentation
- Symposium on Planetary Science 2016, Feb. 2016, Japanese, Sendai, Domestic conferenceSummary of environment of airless bodies, moons, and spacecraftOral presentation
- Symposium on Planetary Science 2016, Feb. 2016, Japanese, Sendai, Domestic conferenceContribution of numerical simulations to planetary exploration missionsOral presentation
- 第12回宇宙環境シンポジウム, Nov. 2015, Japanese, Kitakyushu, Domestic conferenceプラズマシミュレーションを用いたABIE放電室内における中性粒子吸入を考慮したプラズマ生成解析Oral presentation
- 地球電磁気・地球惑星圏学会 第138回総会及び講演会, Oct. 2015, Japanese, Tokyo, Domestic conference月面磁気異常上空の太陽風電子ダイナミクスの3次元シミュレーション解析Oral presentation
- 第58回宇宙科学技術連合講演会, Oct. 2015, Japanese, Kagoshima, Domestic conferenceプラズマシミュレーション援用による大気吸入型イオンエンジン開発に向けたプラズマ解析と実機検証Poster presentation
- Asia Oceania Geosciences Society (AOGS) 2015, Aug. 2015, English, Singapore, International conferenceFull Kinetic Simulations of Plasma Flow Interactions with Meso- and Micro-Scale Magnetic DipolesPoster presentation
- Joint Conference of 30th International Symposium on Space Technology and Science, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Jul. 2015, English, Kobe, International conferenceThree Dimensional Particle-In-Cell Simulation for the Development of Air Breathing Ion EnginePoster presentation
- 12th Interenational School for Space Simulations (ISSS12), Jul. 2015, English, Prague, czech, International conferenceSpacecraft-plasma interactions[Invited]Invited oral presentation
- Joint Conference of 30th International Symposium on Space Technology and Science, 34th International Electric Propulsion Conference and 6th Nano-satellite Symposium, Jul. 2015, English, Kobe, International conferenceNumerical Simulation of ECR Plasma in Air Breathing Ion engine (ABIE): Neutral Gas Density Distribution and ECR Plasma FormationPoster presentation
- JPGU, May 2015, Japanese, Chiba, Domestic conference月面磁気異常上空における太陽風応答の3次元全粒子シミュレーションOral presentation
- WSSIT2015 社会システムと情報技術研究ウィーク, Mar. 2015, Japanese, 北海道, Domestic conferenceマルチエージェントを用いた並列パンデミックシミュレーションOral presentation
- ハイパフォーマンスコンピューティングと計算科学シンポジウム, 2015, Japanese, Domestic conferenceプラズマ粒子シミュレーションのメニーコアプロセッサ向け最適化手法の探求Poster presentation
- 計算工学講演会, 2015, Japanese, Domestic conferenceOptimization of Parallel Plasma Particle Simulations on MIC ArchitectureOral presentation
- Symposium for Space Simulations, 2015, English, International conferenceElectronhybrid simulations of the dependencies of the generation process of whistler modeemissionsPoster presentation
- AGU Fall Meeting, 2015, English, International conferenceDependencies of the Generation Process of Whistler-Mode Emissions on the Kinetic Energy of Anisotropic Electrons in the Earth's Inner MagnetospherePoster presentation
- URSI-Japan Radio Science Meeting, 2015, English, International conferenceDependencies of the Generation Process of Whistler-Mode Emissions on Temperature Anisotropy of Energetic Electrons in the Earth's Inner MagnetosphereInvited oral presentation
- SciTECH2015, Jan. 2015, English, USA, International conferencePIC Simulation on Plasma Flow Response to a Meso-scale Magnetic Dipole in SpaceOral presentation
- 第11回宇宙環境シンポジウム, Dec. 2014, Japanese, Osaka, Domestic conference小型ダイポール磁場のプラズマ流応答に関する3次元粒子シミュレーションOral presentation
- STEシミュレーション研究会, Dec. 2014, Japanese, Tokyo, Domestic conferenceプラズマ粒子シミュレーションのメニーコアアーキテクチャ向け高効率実装の展望Oral presentation
- AGU Fall Meeting, Dec. 2014, English, San Francisco, USA, International conferencePhotoelectron and Secondary Electron Dynamics Around the Solar Probe Plus SpacecraftPoster presentation
- 第11回宇宙環境シンポジウム, Dec. 2014, Japanese, Osaka, Domestic conference3次元PICシミュレーションを用いた大気吸入型イオンエンジン放電室内部におけるプラズマ生成解析Oral presentation
- 平成26年度STE研究集会「太陽圏シンポジウム」および「太陽地球環境と宇宙線モジュレーション」, Nov. 2014, Japanese, Nagoya, Domestic conference太陽風・小型磁気圏相互作用のシミュレーション研究のレビュー[Invited]Nominated symposium
- 地球電磁気・地球惑星圏学会第136回総会・講演会, Nov. 2014, Japanese, Matsumoto, Domestic conferenceFull Particle-In-Cell 3D simulation on the interactions between the solar wind and a lunar magnetic anomalyOral presentation
- 第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, Nagasaki, Domestic conference宇宙機の能動帯電を用いた軌道制御手法の推力特性の評価Oral presentation
- the 24th International TOKI conference (ITC24), Nov. 2014, English, Toki, International conferenceThree-dimensional AMR-PIC simulations on ion beam neutralization in ion enginePoster presentation
- the 24th International TOKI conference (ITC24), Nov. 2014, English, Toki, International conferenceFull kinetic simulations on plasma and field disturbancein the vicinity of spacecraft[Invited]Invited oral presentation
- 第58回宇宙科学技術連合講演会, Nov. 2014, Japanese, Nagasaki, Domestic conference3次元プラズマシミュレーションをもちいた大気吸入型イオンエンジン開発のためのECRプラズマ生成解析Oral presentation
- The 65th International Astronautical Congress, Oct. 2014, English, Tronto,Canada, International conferenceNumerical simulation of spacecraft charging for electromagnetic orbital controlOral presentation
- URSI General Assembly, Aug. 2014, English, Beijing,China, International conferenceFull Full Kinetic Simulation on Plasma Flow Response to a Meso-scale Magnetic Dipole[Invited]Invited oral presentation
- 40th COSPAR Scientific Assembly, Aug. 2014, English, Moscow, Russia, International conferenceElectromagnetic Plasma Particle Simulations on Solar Probe Plus Spacecraft Interaction with Near-Sun Plasma EnvironmentOral presentation
- JHPCN:学際大規模情報基盤共同利用・共同研究拠点 第6回 シンポジウム,, Jul. 2014, Japanese, Tokyo, Domestic conference超並列宇宙プラズマ粒子シミュレーションの研究Nominated symposium
- AOGS 11th Annual Meeting, Jul. 2014, English, Sapporo, International conferenceParticle Simulations of Spacecraft-Plasma Interactions and their Effects on Electric Field MeasurementsPoster presentation
- The 13th Spacecraft Charging Technology Conference, Jun. 2014, English, Pasdena,USA, International conferenceNumerical simulation of satellite charging for propellantless orbital controlOral presentation
- 13th Spacecraft Charging Technology Conference, Jun. 2014, English, Pasadena, USA, International conferenceElectromagnetic Full-Par- ticle Simulations on Spacecraft Interactions with Near-Sun EnvironmentPoster presentation
- JPGU, May 2014, Japanese, Yokohama, Domestic conference小型ダイポール磁場とプラズマ流の相互作用に関する3次元粒子シミュレーションPoster presentation
- JPGU, May 2014, Japanese, Yokohama, Domestic conference計算機実験による宇宙機近傍のプラズマ電磁擾乱の研究[Invited]Invited oral presentation
- JPGU, May 2014, Japanese, Yokohama, Domestic conference荷電粒子ビーム放出を用いた衛星帯電制御の数値シミュレーションPoster presentation
- 京都大学生存圏シンポジウム(KDKシンポジウム), Mar. 2014, Japanese, 京都市, Domestic conference大気吸入型イオンエンジン内のプラズマ生成に関する粒子シミュレーションPoster presentation
- 2014年ハイパフォーマンスコンピューティングと計算科学シンポジウム(HPCS2014), Jan. 2014, Japanese, 東京, Domestic conference適合格子細分化手法を用いたプラズマPICシミュレーションの開発Poster presentation
- 第10回宇宙環境シンポジウム, Dec. 2013, Japanese, JAXA, Tokyo, abbreviated, Domestic conference大気吸入型イオンエンジン放電室内におけるプラズマ生成シミュレーションOral presentation
- 第10回宇宙環境シンポジウム, Dec. 2013, Japanese, JAXA, Tokyo, Domestic conference太陽近傍プラズマ環境下での科学衛星帯電に関する粒子シミュレーションOral presentation
- 第10回宇宙環境シンポジウム, Dec. 2013, Japanese, 東京, Domestic conference計算機実験による宇宙機近傍のプラズマ電磁擾乱の研究[Invited]Invited oral presentation
- AGU Fall meeting, Dec. 2013, English, San Francisco, International conferencePIC simulations on plasma response to a meso-scale magnetic dipolePoster presentation
- AGU Fall Meeting 2013, Dec. 2013, English, American Geophysical Union, San Francisco, USA, International conferenceModeling and Simulations of the Double-Probe Electric Field Instrument in Tenuous and Cold Streaming PlasmasPoster presentation
- SGEPSS Fall Meeting 2013, Nov. 2013, Japanese, Society of Geomagnetism and Earth, Planetary and Space Sciences, Kochi, Domestic conferenceParticle-In-Cell Simulation on Spacecraft Interactions with Solar Coronal PlasmaPoster presentation
- 地球電磁気・地球惑星圏学会 第134回総会及び講演会, Nov. 2013, Japanese, 高知市, Domestic conference荷電粒子ビーム放出による衛星帯電現象の解析Poster presentation
- 関西支部 第443回航空懇談会, Sep. 2013, Japanese, 神戸市, Domestic conference粒子シミュレーションによる宇宙機近傍プラズマ電磁擾乱の研究[Invited]Invited oral presentation
- Sokendai Asian Winter School(総研大アジア冬の学校2012), Sep. 2013, English, 土岐市, Domestic conferencePlasma Particle Simulation[Invited]Invited oral presentation
- AP-RASC 2013, Sep. 2013, English, Taipei, International conferencePIC Simulation on the Solar Wind Interactions with a Meso Scale Magnetic DipoleOral presentation
- Asia-Pacific Radio Science Conference (AP-RASC) 2013, Sep. 2013, English, National Taiwan University, Taipei, Taiwan, International conferenceFull Particle Simulations on Space Plasma Interactions with Scientific Satellite[Invited]Invited oral presentation
- The 11th International School Symposium for Space Simulations, Aug. 2013, English, abbreviated, International conferenceMicrowave Plasma Simulation for the Development of Air Breathing Ion EngineOral presentation
- the 11th International School for Space Simulations (ISSS-11), Jul. 2013, English, Taiwan, International conferenceSpacecraft-plasma interactions[Invited]Invited oral presentation
- 11th International School/Symposium for Space Simulations, Jul. 2013, English, National Central University, Jhongli, Taiwan, International conferenceParticle Simulations of Electromagnetic Environment around Scientific Spacecraft[Invited]Invited oral presentation
- The 11th International School for Space Simulation (ISSS11), Jul. 2013, English, Taipei, International conferenceParticle-in-cell simulation on the interactions between the solar wind and a magnetic anomaly on the moonPoster presentation
- The 11th International School for Space Simulation (ISSS11), Jul. 2013, English, Taipei, International conferenceMicrowave plasmasimulation for the development of air breathing ion enginePoster presentation
- The 11th International School for Space Simulation (ISSS11), Jul. 2013, English, Taipei, International conferenceElectromagnetic field treatment in AMR-PIC codePoster presentation
- The 11th International School for Space Simulation (ISSS11), Jul. 2013, English, Taipei, International conferenceDevelopment of a module for adaptive mesh refinement simulationsPoster presentation
- 計算工学講演会 2013, Jun. 2013, Japanese, 東京大学生産研, Domestic conference適合格子細分化プラズマ粒子シミュレーションにおける動的負荷バランス手法Oral presentation
- AOGS, Jun. 2013, English, Brisbane Australia, International conferencePIC Simulation on the Solar Wind Interactions a small-scale magnetic dipole[Invited]Invited oral presentation
- The 29th International Space Technology and Sciences, Jun. 2013, English, JSASS, Nagoya, abbreviated, International conferenceMicrowave plasma simulation for the development of air breathing ion engineOral presentation
- 2013 International Supercomputing Conference (ISC' 13), Jun. 2013, English, Leipzig, International conferenceDevelopment of Parallelized Plasma PIC Simulation Code with Adaptive Mesh RefinementPoster presentation
- 日本地球惑星科学連合2013年大会, May 2013, Japanese, 千葉市, Domestic conference太陽風プラズマと月面局所磁場の相互作用に関する粒子シミュレーションPoster presentation
- Japan Geoscience Union Meeting 2012, May 2013, Japanese, Japan Geoscience Union, Chiba, Domestic conferenceInternational Collaborative Study on Spacecraft-Plasma Interactions in the Near-Sun EnvironmentOral presentation
- 日本地球惑星科学連合2013年大会, May 2013, Japanese, 千葉市, Domestic conferenceプラズマ粒子シミュレーションによる太陽風-小型ダイポール磁場相互作用の解析とそのReiner Gamma磁場への応用Oral presentation
- EGU 2013, Apr. 2013, English, Vienna Austria, International conferenceFull Particle-In-Cell simulations on the solar wind interactions with a small-scale magnetic dipole[Invited]Invited oral presentation
- 日本物理学会 「プラズマ宇宙物理」3学会合同セッション, Mar. 2013, Japanese, 日本物理学会, Hiroshima,Japan, Domestic conference適合格子細分化法を用いた粒子シミュレーションの動的負荷バランス手法Oral presentation
- 京都大学 平成24年度RISH電波科学計算機実験シンポジウム, Mar. 2013, Japanese, 京都大学 生存圏研究所, Uji,Japan, Domestic conference適合格子細分化プラズマ粒子シミュレーションコードの高効率並列化手法に関する研究Public symposium
- 京都大学 平成24年度RISH電波科学計算機実験シンポジウム, Mar. 2013, Japanese, 京都大学 生存圏研究所, Uji,Japan, Domestic conference小型ダイポール磁場と太陽風の相互作用に関するAMR-PICシミュレーションPublic symposium
- 核融合科学研究所 一般共同研究成果報告会, Jan. 2013, Japanese, nifs, Toki,Japan, Domestic conference適合格子細分化法によるマルチスケールコードの開発と従来法への応用Oral presentation
- 情報処理学会 2013年ハイパフォーマンスコンピューティングと計算科学シンポジウム, Jan. 2013, Japanese, 情報処理学会, Tokyo,Japan, Domestic conference適合格子細分化プラズマ粒子シミュレーションにおける動的負荷バランス手法の開発Poster presentation
- AGU Fall Meeting 2012, Dec. 2012, English, American Geophysical Union, San Francisco, USA, International conferencePlasma Particle Simulations on Interactions Between Spacecraft and Cold Streaming PlasmasPoster presentation
- 日本航空宇宙学会 第56回宇宙科学技術連合講演会, Nov. 2012, Japanese, Beppu, Japan, Domestic conferenceダイポール磁場中へのプラズマ放出によるプラズマセイルの磁気帆拡大Oral presentation
- JIFT 2012, "Innovative methods in Plasma Particle Simulations", Nov. 2012, English, NIFS, Providence, USA, International conferenceParallelized Adaptive Mesh Refinement Particle-In-Cell Scheme with Dynamics Domain Decomposition[Invited]Invited oral presentation
- NIFS, The 22nd International Toki Conference, Nov. 2012, English, NIFS, Toki,Japan, International conferenceNumerical Simulation of Dipolar Magnetic Field Inflation by Equatorial Ring-currentPoster presentation
- The 2nd International Symposium on Large-Scale Computational Science and Engineering, Nov. 2012, English, JST, Tokyo,Japan, International conferenceMulti-scale Plasma Particle Simulation for the Development of Interplanetary Flight System[Invited]Invited oral presentation
- NIFS, The 22nd International Toki Conference, Nov. 2012, English, NIFS, Toki,Japan, International conferenceDevelopment of Parallelized AMR-PIC Plasma Simulation Code with Dynamic Domain Decomposition,Poster presentation
- NIFS, The 22nd International Toki Conference, Nov. 2012, English, NIFS, Toki,Japan, International conferenceDevelopment of an AMR Module for Various Numerical SimulationsPoster presentation
- NIFS, The 22nd International Toki Conference, Nov. 2012, English, NIFS, Toki,Japan, International conference2D AMR-PIC Plasma Simulation for Mini-Magnetosphere of Magnetized ObjectsPoster presentation
- 22nd International Toki Conference, Nov. 2012, English, Toki, International conference2D AMR-PIC Plasma Simulation for Mini-Magnetosphere of Magnetized ObjectsPoster presentation
- SGEPSS Fall Meeting 2012, Oct. 2012, Japanese, Society of Geomagnetism and Earth, Planetary and Space Sciences, Sapporo, Domestic conferenceParticle Simulations on Properties of a Spacecraft Wake and Its Effects on Double-Probe Measurements in Earth's MagnetosphereOral presentation
- 地球電磁気・地球惑星圏学会 第132回総会及び講演会, Oct. 2012, Japanese, SGEPSS, Sapporo,Japan, Domestic conference太陽風-小型ダイポール磁場の相互作用に関する2 次元AMR-PIC シミュレーションOral presentation
- ・地球電磁気・地球惑星圏学会第132回総会及び講演会, Oct. 2012, Japanese, 札幌市, Domestic conference太陽風-小型ダイポール磁場の相互作用に関する2次元AMR-PICシミュレーションOral presentation
- 地球電磁気・地球惑星圏学会 第132回総会及び講演会, Oct. 2012, Japanese, SGEPSS, Sapporo,Japan, Domestic conferenceイオンエンジンビームの電子‐イオンカップリングに関する粒子シミュレーションOral presentation
- Conference on Computational Physics (CCP2012), Oct. 2012, English, Kobe, International conferenceTwo-Dimensional AMR-PIC Simulation on Solar Wind Interaction with Mini-MagnetospherePoster presentation
- Conference on Computational Physics (CCP2012), Oct. 2012, English, Kobe,Japan, International conferenceFull Particle-In-Cell Simulation of Ion Beam NeutralizationPoster presentation
- Conference on Computational Physics (CCP2012), Oct. 2012, English, Kobe,Japan, International conferenceDevelopment of Parallelized Adaptive Mesh Refinement Particle in Cell with Dynamic Domain DecompositionPoster presentation
- Conference on Computational Physics 2012, Oct. 2012, English, Osaka University, Kobe, International conferenceDevelopment of a Scalable PIC Simulator and Its Application to Spacecraft Interaction with Streaming PlasmaPoster presentation
- Conference on Computational Physics (CCP2012), Oct. 2012, English, Kobe,Japan, International conferenceDevelopment of a portable AMR module for various numerical simulationsPoster presentation
- 核融合科学研究所 プラズマシミュレータシンポジム 2012, Sep. 2012, Japanese, NIFS, Toki,Japan, Domestic conference適合格子細分化法を用いた粒子コードの開発と並列化[Invited]Invited oral presentation
- プラズマシミュレーターシンポジウム2012, Sep. 2012, Japanese, 土岐市, Domestic conference小型磁気圏の2次元AMR-PICシミュレーションPoster presentation
- JSST 2012 - International Conference on Simulation Technology, Sep. 2012, English, Japan Society for Simulation Technology, Kobe, International conferenceDevelopment of a Scalable PIC Simulator and Its Application to Spacecraft-Plasma Interaction ProblemsOral presentation
- JSST2012 International Conference on Simulation Technology, Sep. 2012, English, Kobe, International conferenceAMR-PIC Simulation on Solar Wind Interaction with Kinetic Scale MagnetosphereOral presentation
- 学際大規模情報基盤共同利用・共同研究拠点第3回シンポジウム, Jul. 2012, Japanese, JHPCN, Tokyo,Japan, Domestic conference超並列宇宙プラズマ粒子シミュレーションの研究Oral presentation
- 第44回流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2012, Jul. 2012, Japanese, Toyama, Japan, Domestic conference磁気プラズマセイル開発に向けたプラズマ粒子シミュレーションコードの高速化Oral presentation
- The 10th International Meeting on High-Performance Computing for Computational Science (VECPAR 2012), Jul. 2012, English, Kobe,Japan, International conferenceParallelized Adaptive Mesh Refinement Particle-In-Cell Scheme with Dynamic Domain DecompositionPoster presentation
- VECPAR 2012 - 10th International Meeting, Jul. 2012, English, RIKEN Advanced Institute for Computational Science, Kobe, International conferenceDevelopment of a Scalable PIC Simulator for Spacecraft-Plasma Interaction ProblemsPoster presentation
- Japan Geoscience Union Meeting 2012, May 2012, Japanese, Japan Geoscience Union, Chiba, Domestic conferencePlasma Particle Simulations on Spacecraft Wake Effects on Electric Field MeasurementsOral presentation
- JPGU 日本地球惑星科学連合2012年大会, May 2012, Japanese, JPGU, Makuhari,Japan, Domestic conferenceイオンエンジン局所ビームの中和電子ダイナミクスに関する粒子シミュレーションPoster presentation
- 12th Spacecraft Charging Technology Conference, May 2012, English, Mengu Cho, Kitakyushu, International conferenceParticle Simulations of Wake Effects on Electric Field Measurements in Multi-species Cold Ion FlowsPoster presentation
- 計算工学学会 第17回計算工学講演会, May 2012, Japanese, 計算工学会, Kyoto,Japan, International conferenceGPGPUによるプラズマ粒子シミュレーションOral presentation
- The12th Spacecraft Charging Technology Conference, May 2012, English, Kyushu Institute of Technology, Kitakyushu,Japan, International conferenceFull PIC Simulation of Ion Beam NeutralizationPoster presentation
- 名古屋大学太陽地球環境研究所研究集会 プラズママルチスケールシミュレーションの現状と展望, Mar. 2012, Japanese, 名古屋大学, Hiroshima, Japan, Domestic conference適合格子細分化法を用いたPICシミュレーション[Invited]Invited oral presentation
- The 7th EU-Japan Joing Symposium on Plasma Processing, Jan. 2012, English, Osaka University, 奈良市, International conferencePlasma Particle Simulation toward the Development of Advanced Space Propulsion[Invited]Invited oral presentation
- 2011 US-Japan JIFT Workshop, Dec. 2011, English, Hiroaki Ohtani, Alex Arefiev, 核融合科学研究所, International conferenceA Scalable Load-Balancing Algorithm for Massively-Parallel Plasma Particle SimulationsInvited oral presentation
- Plasma conference 2011, Nov. 2011, Japanese, プラズマ・核融合学会, 金沢市, International conference先端宇宙推進開発に向けたプラズマ粒子シミュレーション研究[Invited]Invited oral presentation
- Plasma conference 2011, Nov. 2011, Japanese, プラズマ・核融合学会, 金沢市, International conference小型磁気圏-太陽風相互作用に関するマルチスケール粒子シミュレーションOral presentation
- 地球電磁気・地球惑星圏学会 第130回総会及び講演会, Nov. 2011, Japanese, 地球電磁気・地球惑星圏学会, 神戸市, Domestic conference小型ダイポール磁場構造と太陽風の相互作用に関する粒子シミュレーションOral presentation
- 第55回宇宙科学技術連合講演会, Nov. 2011, Japanese, 日本航空宇宙学会, 愛媛市, Domestic conference磁気プラズマセイルへの応用に向けたコイル磁場中のリングカレント生成による磁気圏拡大評価Oral presentation
- Plasma conference 2011, Nov. 2011, Japanese, プラズマ・核融合学会, 金沢市, International conference磁気プラズマセイルへの応用に向けたコイル磁場中のリングカレント生成による磁気圏拡大評価Poster presentation
- 第55回宇宙科学技術連合講演会, Nov. 2011, Japanese, 日本航空宇宙学会, 愛媛市, Domestic conference磁気セイルの推力・トルク特性に関する2次元Hybrid-PICシミュレーションOral presentation
- 地球電磁気・地球惑星圏学会(SGEPSS)秋学会, Nov. 2011, Japanese, 神戸大学, Domestic conference衛星搭載電界センサー計測におけるスプリアス電界特性に関する計算機実験Poster presentation
- International Toki Conference (ITC 2011), Nov. 2011, English, National Institute for Fusion Sciences(NIFS), 土岐市, International conferenceDynamic Domain Decomposition for 3D PIC simulation with Adaptive Mesh RefinementPoster presentation
- JIFT Workshop 2011, Nov. 2011, English, National Institute for Fusion Sciences(NIFS), 土岐市, International conferenceA multi-scale electromagnetic particle code with adaptive mesh refinement and its parallelization[Invited]Invited oral presentation
- 第1回大規模計算科学 国際シンポジウム, Oct. 2011, Japanese, 日本学術会議, JST, 東京都, International conference惑星間航行システム開発に向けたマルチスケール粒子シミュレーション[Invited]Invited oral presentation
- 第8回宇宙環境シンポジウム, Oct. 2011, Japanese, JAXA, 東京都, Domestic conference小型ダイポール磁場構造と太陽風の相互作用に関する粒子シミュレーションOral presentation
- 第8回宇宙環境シンポジウム, Oct. 2011, Japanese, 東京ビックサイト, Domestic conference衛星帯電環境下におけるダブルプローブ電場観測に関するプラズマ粒子シミュレーションOral presentation
- International conference on numerical simulations of plasmas (ICNSP 2011),, Sep. 2011, English, Princeton Plasma Physics Laboratory (PPPL), Long Branch, USA, International conferenceModification of Electromagnetic Hybrid Particle-In-Cell Plasma Simulation Model for Robustness Improvement,Poster presentation
- International conference on numerical simulations of plasmas (ICNSP 2011),, Sep. 2011, English, Princeton Plasma Physics Laboratory (PPPL), Long Branch, USA, International conferenceDynamic Domain Decomposition for 3D PIC simulation with Adaptive Mesh Refinement,Poster presentation
- The XXXth URSI General Assembly and Scientific Symposium, Aug. 2011, English, A. Hamit Serbest, Istanbul, Turkey, International conferencePlasma Particle Simulations on Electric Antenna and Spacecraft EnvironmentInvited oral presentation
- 学際大規模情報基盤共同利用・共同研究拠点第3回シンポジウム, Jul. 2011, Japanese, 東京大学情報基盤センター, 東京都, Domestic conference超並列宇宙プラズマ粒子シミュレーションの研究Oral presentation
- 10th International School for Space Simulations (ISSS), Jul. 2011, English, Society of Alberta University, Banff, Canada, International conferencePlasma particle simulation with GPGPUPoster presentation
- The 10th International School/Symposium for Space Simulations, Jul. 2011, English, R. D. Sydora, R. Marchand, Banff, Canada, International conferenceParticle-In-Cell Simulations on Plasma Environment Around Spacecraft-Onboard Electric Field SensorsPoster presentation
- 10th International School for Space Simulations (ISSS), Jul. 2011, English, Society of Alberta University, Banff, Canada, International conferenceParticle-in-Cell simulation on spacecraft plasma environment using EMSES-Development of a GUI tool for satellite modelingPoster presentation
- 10th International School for Space Simulations (ISSS), Jul. 2011, English, Society of Alberta University, Banff, Canada, International conferenceParallelization of plasma particle simulation with dynamic domain decompositionPoster presentation
- 10th International School for Space Simulations (ISSS), Jul. 2011, English, Society of Alberta University, Banff, Canada, International conferenceFull PIC simulation on solar wind interaction with a small-scale artificial magnetosphere[Invited]Invited oral presentation
- International Conference on Computational Science, Jun. 2011, English, Nanyang Technological University, Singapore, International conferenceA Multi-Scale Electromagnetic Particle Code with Adaptive Mesh Refinement and Its ParallelizationPoster presentation
- 日本地球惑星科学連合2011年大会, May 2011, Japanese, JPGU, 千葉市, Domestic conference双極子型磁気シールドを用いた相対論的太陽宇宙線遮蔽の数値解析Poster presentation
- 日本地球惑星科学連合2011年大会, May 2011, Japanese, JPGU, 千葉市, Domestic conference小型ダイポール磁場と太陽風の相互作用に関する粒子シミュレーションOral presentation
- 日本地球惑星科学連合2011年大会, May 2011, Japanese, JPGU, 千葉市, Domestic conference磁気セイル周りの太陽風プラズマ挙動に関する2次元Hybrid-PICシミュレーションPoster presentation
- 日本地球惑星科学連合2011年大会, May 2011, Japanese, 幕張メッセ国際会議場, Domestic conference科学衛星搭載用電界センサー周辺の光電子環境に関する計算機実験Poster presentation
- RISH 電波科学計算機実験(KDK)シンポジウム, Mar. 2011, Japanese, 京都大学 生存圏研究所, 宇治市, Domestic conference動的領域分割を用いたプラズマ電磁粒子コードのプロセス並列手法の開発Poster presentation
- RISH 電波科学計算機実験(KDK)シンポジウム, Mar. 2011, Japanese, 京都大学 生存圏研究所, 宇治市, Domestic conference数値シミュレーションを用いた磁気プラズマセイルの推力評価Poster presentation
- RISH 電波科学計算機実験(KDK)シンポジウム, Mar. 2011, Japanese, 京都大学 生存圏研究所, 宇治市, Domestic conference磁気セイルにおける小型磁気圏-太陽風相互作用Poster presentation
- RISH 電波科学計算機実験(KDK)シンポジウム, Mar. 2011, Japanese, 京都大学 生存圏研究所, 宇治市, Domestic conference宇宙プラズマ環境における電界アンテナ特性に関する計算機実験Poster presentation
- 第51回 航空原動機・宇宙推進講演会, Mar. 2011, Japanese, 日本航空宇宙学会, 広島市, Domestic conferenceダイポール磁場中のリングカレント生成に関する3次元ハイブリッド粒子シミュレーションOral presentation
- 第196回生存圏シンポジウム、平成23年度 RISH電波科学計算機実験(KDK)シンポジウム, Feb. 2011, Japanese, 京都大学生存圏研究所, 宇治市, Domestic conference適合格子細分化法を用いたプラズマ粒子シミュレーションコードのプロセス並列手法に関する研究Poster presentation
- 第196回生存圏シンポジウム、平成23年度 RISH電波科学計算機実験(KDK)シンポジウム, Feb. 2011, Japanese, 京都大学生存圏研究所, 宇治市, Domestic conference数値シミュレーションを用いた磁気プラズマセイルの推力評価Poster presentation
- 第196回生存圏シンポジウム、平成23年度 RISH電波科学計算機実験(KDK)シンポジウム, Feb. 2011, Japanese, 京都大学生存圏研究所, 宇治市, Domestic conference磁気プラズマセイル開発に向けた全粒子シミュレーションPoster presentation
- 第196回生存圏シンポジウム、平成23年度 RISH電波科学計算機実験(KDK)シンポジウム, Feb. 2011, Japanese, 京都大学生存圏研究所, 宇治市, Domestic conferenceイオンエンジン搭載宇宙機のプラズマ環境に関する三次元粒子シミュレーションPoster presentation
- 第196回生存圏シンポジウム、平成23年度 RISH電波科学計算機実験(KDK)シンポジウム, Feb. 2011, Japanese, 京都大学生存圏研究所, 宇治市, Domestic conference2次元Hybrid-PICシミュレーションによる磁気セイルの推進特性Poster presentation
- 平成22年度宇宙輸送シンポジウム, Jan. 2011, Japanese, JAXA/ISAS, 相模原市, Domestic conferenceイオン慣性長スケールにおける磁気セイルの推力特性に関する3次元ハイブリッド粒子シミュレーションOral presentation
- 第11回宇宙科学シンポジウム, Jan. 2011, Japanese, JAXA/ISAS, 相模原市, Domestic conference3次元ハイブリッド粒子シミュレーションによるプラズマセイルの推進性能評価Poster presentation
- 20th International Toki Conference, Dec. 2010, English, National Institute for Fusion Science, Ceratopia Toki, International conferenceMPI parallelization of full PIC simulation code with Adaptive Mesh RefinementOral presentation
- 20th International Toki Conference, Dec. 2010, English, Ceratopia Toki, 土岐市, International conferenceFull particle-in-cell simulation study on solar wind interaction with a small scale artificial magnetospherePoster presentation
- 科学技術振興機構JST-CREST「マルチスケール・マルチフィジックス現象の統合シミュレーション」研究領域平成22年度公開シンポジウム, Nov. 2010, Japanese, JST, 東京都, Domestic conference惑星間航行システム開発に向けたマルチスケール粒子シミュレーションOral presentation
- 第54回宇宙科学技術連合講演会, Nov. 2010, Japanese, 日本航空宇宙学会, 静岡市, Domestic conference有人宇宙飛行へ向けた磁気シールドの数値解析Oral presentation
- 第54回宇宙科学技術連合講演会, Nov. 2010, Japanese, 日本航空宇宙学会, 静岡市, Domestic conference先端宇宙推進開発へのプラズマシミュレーション利用Oral presentation
- 第54回宇宙科学技術連合講演会, Nov. 2010, Japanese, 日本航空宇宙学会, 静岡市, Domestic conference磁気プラズマセイルの開発に向けたハイブリッド粒子シミュレーションOral presentation
- 52nd Annual Meeting of the APS Division of Plasma Physics, Nov. 2010, English, American Physics Society, Chicago, USA, International conferenceMPI parallelization of full PIC simulation code with Adaptive Mesh RefinementOral presentation
- 52nd Annual Meeting of the APS Division of Plasma Physics, Nov. 2010, English, American Physics Society, Chicago, USA, International conferenceFull particle-in-cell simulation study on solar wind interaction with a small scale magnetospherePoster presentation
- JIFT2010 (Workshop on development of simulation science in plasma physics), Nov. 2010, English, National Institute for Fusion Science, Chicago, USA, International conferenceDevelopment of a multi-scale PIC code using AMR and its MPI parallelization.(part II)Oral presentation
- JIFT2010 (Workshop on development of simulation science in plasma physics), Nov. 2010, English, National Institute for Fusion Science, Chicago, USA, International conferenceDevelopment of a multi-scale PIC code using AMR and its MPI parallelization.(part I)Oral presentation
- 第7回宇宙環境シンポジウム, Oct. 2010, Japanese, JAXA, 東京都, Domestic conference双極子型磁気シールドを用いた宇宙線遮蔽の数値解析Oral presentation
- 第7回宇宙環境シンポジウム, Oct. 2010, Japanese, JAXA, 東京都, Domestic conference人工小型磁気圏と太陽風の相互作用に関するプラズマ粒子シミュレーションOral presentation
- 第128回地球電磁気・地球惑星圏学会秋学会, Oct. 2010, Japanese, 地球電磁気・地球惑星圏学会, 那覇市, Domestic conference小型磁気圏と太陽風の相互作用に関する粒子シミュレーションOral presentation
- 第128回地球電磁気・地球惑星圏学会秋学会, Oct. 2010, Japanese, 地球電磁気・地球惑星圏学会, 那覇市, Domestic conference光電子環境における衛星搭載電界センサー特性に関する計算機実験Oral presentation
- 第7回宇宙環境シンポジウム, Oct. 2010, Japanese, JAXA, 東京都, Domestic conferenceソーラーセイル周辺のプラズマ挙動と帯電特性に関する数値シミュレーションOral presentation
- 第4回シミュレーション科学シンポジウム, Sep. 2010, Japanese, 核融合科学研究所, 核融合科学研究所, Domestic conferenceマルチスケールプラズマ粒子シミュレーションにおける階層間接続Poster presentation
- Asia-Pacific Radio Science Conference, Sep. 2010, English, URSI, 富山市, International conferenceSOLAR WIND INTERACTION WITH A SMALL SCALE ARTIFICIAL MAGNETOSPHERE FOR MAGNETO-PLASMA SAILOral presentation
- 2nd international symposium on radio systems and space plasma, Aug. 2010, English, Blagovest Shishkov, Sofia, Bulgaria, International conferencePlasma Particle Simulation on Interactions Between an Artificial Small Magnetosphere and the Solar Wind[Invited]Invited oral presentation
- 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Jul. 2010, English, AIAA, Nashville, USA, International conferenceThrust Evaluation of Magneto Plasma Sail by Using Three-Dimensional Hybrid PIC CodeOral presentation
- 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Jul. 2010, English, AIAA, Nashville, USA, International conferenceExperimental and Numerical Investigations on the Thrust Production Process of Magnetoplasma SailOral presentation
- 第11回光量子科学研究シンポジウム, Jun. 2010, Japanese, 日本原子力研究開発機構, 木津川市, Domestic conference太陽風から電磁気学的推力を得る磁気プラズマセイルの推力評価Poster presentation
- 日本地球惑星科学連合2010年大会, May 2010, Japanese, 日本地球惑星科学連合, 千葉市, Domestic conference磁気プラズマセイルの磁気圏展開に関する電磁粒子シミュレーションOral presentation
- 日本地球惑星科学連合2010年大会, May 2010, Japanese, 日本地球惑星科学連合, 千葉市, Domestic conference磁気プラズマセイルにおける人工磁気圏展開と太陽風相互作用Oral presentation
- MPSシンポジウム, Mar. 2010, Japanese, JAXA, 京都市,龍谷大学, Domestic conferenceCREST/JST研究プロジェクトの概要Oral presentation
- 第10回宇宙科学シンポジウム, Jan. 2010, Japanese, JAXA, 相模原市(JAXA), Domestic conferenceプラズマセイル飛翔実験機の研究Oral presentation
- 宇宙輸送シンポジウム, Jan. 2010, Japanese, JAXA, 相模原市(JAXA), Domestic conference3次元ハイブリッド粒子モデルによる磁気プラズマセイルの推力評価Oral presentation
- 第2回宇宙環境利用シンポジウム(第133回生存圏シンポジウム), Dec. 2009, Japanese, 京都大学生存圏研究所, 京都市,京都大学, Domestic conference磁気プラズマセイル開発に 向けた数値シミュレーションOral presentation
- 宇宙航行の力学シンポジウム, Dec. 2009, Japanese, JAXA, 相模原市, JAXA, Domestic conference磁気プラズマセイルのプラズマ粒子シミュレーション解析Oral presentation
- 独立行政法人 科学技術振興機構JST-CREST「マルチスケール・マルチフィジックス現象の統合シミュレーション」研究領域 平成21年度公開シンポジウム, Nov. 2009, Japanese, JST, 東洋大学, Domestic conference惑星間航行システム開発に向けたマルチスケール粒子シミュレーションPublic symposium
- 第6回宇宙環境シンポジウム, Oct. 2009, Japanese, JAXA, 九州工業大学, 北九州国際会議場, Domestic conference惑星間航行に向けたソーラーセイル周辺のプラズマ挙動基礎解析Oral presentation
- 第6回宇宙環境シンポジウム, Oct. 2009, Japanese, JAXA, 九州工業大学, 北九州国際会議場, Domestic conference宇宙機環境プラズマ解析の高解像度化Oral presentation
- The 6th space environment symposium, Oct. 2009, English, JAXA, Kita-Kyushu, International Conference Center, International conferencePlasma simulation team, JEDI Plasma simulation team, Particle-In-Cell Simulations on the interactions between Space plasma and advanced propulsion system[Invited]Invited oral presentation
- International Conference on Numerical Simulation of Plasmas, Oct. 2009, English, Institute for Plasmas and Nuclear Fusion, Lisbon, International conferencePlasma Particle Simulation for the Development of Interplanetary Flight SystemOral presentation
- International Conference on Numerical Simulation of Plasmas, Oct. 2009, English, Institute for Plasmas and Nuclear Fusion, Lisbon, International conferenceFull PIC simulation study on magnetic inflation around a magneto plasma sail (MPS)Poster presentation
- International Conference on Numerical Simulation of Plasmas, Oct. 2009, English, Institute for Plasmas and Nuclear Fusion, Lisbon, International conferenceApplying a Multigrid Method to Analysis of Spacecraft-Plasma Interactions using Electrostatic Particle-In-Cell Simulations (II)Poster presentation
- International Conference on Numerical Simulation of Plasmas, Oct. 2009, English, Institute for Plasmas and Nuclear Fusion, Lisbon, International conferenceApplying a Multigrid Method to Analysis of Spacecraft-Plasma Interactions using Electrostatic Particle-In-Cell SimulationsPoster presentation
- International Conference on Numerical Simulation of Plasmas, Oct. 2009, English, Institute for Plasmas and Nuclear Fusion, Lisbon, International conferenceA multi-scale electromagnetic particle code with adaptive mesh refinement and its parallelizationPoster presentation
- International Conference on Numerical Simulation of Plasmas, Oct. 2009, English, Institute for Plasmas and Nuclear Fusion, Lisbon, International conference3D Electromagnetic Particle-In-Cell Simulation of Microwave MagnetronPoster presentation
- 第126回 地球電磁気・地球惑星圏学会(SGEPSS), Sep. 2009, Japanese, 地球電磁気・地球惑星圏学会, 石川県, 金沢大学, Domestic conference小型人工磁気圏と衛星噴射プラズマおよび太陽風の相互作用Oral presentation
- 第53回宇宙科学技術連合講演会, Sep. 2009, Japanese, 日本地球惑星科学連合, 京都市,京都大学, Domestic conference磁気プラズマセイルで用いられるプラズマ噴射による磁気圏拡大の3次元ハイブリッド粒子シミュレーションOral presentation
- 第126回地球電磁気・地球惑星圏学会秋学会, Sep. 2009, Japanese, SGEPSS, 金沢大学角間キャンパス, Domestic conference衛星周辺プラズマ電磁環境解析のための粒子シミュレーション技法の開発と応用Oral presentation
- 第53回宇宙科学技術連合講演会, Sep. 2009, Japanese, 日本地球惑星科学連合, 京都市,京都大学, Domestic conference宇宙機環境プラズマ解析へのNested Gridの適用検討Oral presentation
- The 7th International Symposium on Applied Plasma Science, Aug. 2009, English, Joining and Welding Research Institute, Osaka University, Hamburg, Germany, International conferenceNumerical Study of an Inflation of a Dipolar Magnetic Field by Plasma Jet Injection in Magneto Plasma SailOral presentation
- International school/symposium for space simulations (ISSS-9), Jul. 2009, English, the University of Versailles Saint-Quentin (UVSQ), France, Saint-Quentin-En-Yvelines, International conferenceMULTI-SCALE PLASMA PARTICLE SIMULATION FOR THE DEVELOPMENT OF INTERPLANETARY FLIGHT SYSTEMPoster presentation
- 27th International Symposium on Space Technology and Science, Jul. 2009, English, 日本航空宇宙学会, つくば市, International conferenceModification of a three-dimensional electrostatic Particle-In-Cell code Adopting a Nested gridOral presentation
- 27th International Symposium on Space Technology and Science, Jul. 2009, English, 日本航空宇宙学会, つくば市, International conferenceMagnetic Inflation of Magnetic Plasma Sail by One Component Plasma SimulationOral presentation
- International school/symposium for space simulations (ISSS-9), Jul. 2009, English, the University of Versailles Saint-Quentin (UVSQ), France, Saint-Quentin-En-Yvelines, International conferenceDevelopment of Electromagnetic Spacecraft Environment Simulator (EMSES)Poster presentation
- The 27th International Symposium on Space Technology and Science, Jul. 2009, English, 日本航空宇宙学会, つくば市, International conference3D Hybrid Simulation of Pure Magnetic Sail including Ion-Neutral Collision Effect in LaboratoryOral presentation
- 日本地球惑星科学連合2009年大会, May 2009, Japanese, JpGU, 幕張メッセ国際会議場, Domestic conference将来衛星搭載用電界アンテナのプラズマ波動受信特性評価に関する計算機実験Oral presentation
- 日本地球惑星科学連合2009年大会, May 2009, Japanese, 日本地球惑星科学連合, 千葉市, 幕張メッセ 国際会議場, Domestic conference衛星からのプラズマ噴射による小型人工磁気圏の展開プロセスOral presentation
- 日本航空宇宙学会第40回年会講演会, Apr. 2009, Japanese, 日本航空宇宙学会, 調布市, Domestic conference3次元ハイブリッドコードを用いた磁気セイル地上実験の数値解析Oral presentation
- IVEC, Apr. 2009, English, IEEE, Monterey, California, USA, International conference3D Electromagnetic Particle-In-Cell Simulations of a Magnetron Based on the Realistic ModelPoster presentation
■ Works
■ Research Themes
- 科学研究費補助金/基盤研究(B), Apr. 2016 - Mar. 2020, Principal investigatorCompetitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, Kobe University, 01 Apr. 2015 - 31 Mar. 2018Computer-aided evaluation of air-intake systems on air breathing ion engine and its experimental verificationsThe purpose of this project is to establish the design guideline of the air intake system for air breathing ion engine (ABIE) both by numerical simulations and experiments. The results of DSMC simulations show that the density of the reflected molecules are concentrated near the center axis of the ABIE. Plasma simulation performed by computational code (EMSES) indicated that the production of the ions in the ABIE increased 5 times by tuning the ABIE design. The experiments using 25% scale ABIE model was carried out. The pressure in the ABIE was measured by the fast ionization gauge. An evaluation method of air intake of ABIE in the orbit (continuous atomic oxygen flow) was successfully established based on the ground-based experiment using beam pulses formed in the laser-detonation beam source.
- 兵庫県, 放射光・スパコン相互利用促進事業, 2017, Principal investigator放射光・スパコン相互利用促進事業補助金Competitive research funding
- 学術研究助成基金助成金/挑戦的萌芽研究, Apr. 2013 - Mar. 2016, Principal investigatorCompetitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Kobe University, 01 Apr. 2013 - 31 Mar. 2015Large-Scale Particle Simulations on Spacecraft Interactions with Extreme Space Plasma EnvironmentWe study the scientific spacecraft interactions with near-Sun plasma environment via three-dimensional electromagnetic plasma particles simulations. The major results of the present study are summarized as below, and the obtained knowledge is applicable to future scientific spacecraft design. 1. Although a large flux of photoelectrons is emitted from s spacecraft, the spacecraft in near-Sun environment charges negatively due to space-charge effects associated with the emitted electrons. 2. The photoelectron distribution shows clear asymmetry near the spacecraft due to an ambient electric field associated with the plasma convection. This environmental asymmetry results in an intense spurious electric field of 100 mV/m. 3. The large flux of photoelectrons causes local magnetic perturbation around the spacecraft, which is in the order of a few nT.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, Kobe University, 01 Apr. 2013 - 31 Mar. 2015A feasibility study on the operation of reactive air breathing ion engine in sub-LEOAir breathing ion engine (ABIE) was experimentally investigated by the laser-detonation atomic beam source which enables to reproduce 8 km/s atomic oxygen (AO) flow in low earth orbit. Electron cyclotron resonance (ECR) microwave plasma was successfully generated by 8 km/s AO and N2 flow. This is the world’s first demonstration of ABIE operation in a simulated space environment by a ground-based facility. The maximum thrust of 0.12 mN was measured. On the other hand, computational simulation of microwave discharge in ABIE suggested the importance of the mesh locations in the discharge chamber which reflects the microwave power while incoming neutrals are transmitted. It was also suggested that the design of the reflectors in the air-inlet of ABIE is essential to increase the molecular density near the microwave antenna where many ions are generated. A physics of the hyperthermal molecular scattering at the solid surface needs to be considered in a future ABIE/RABIE work.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Kyoto University, 01 Apr. 2011 - 31 Mar. 2015Tiny plasma wave instruments opening science with high spatial resolutions in spaceWe miniaturized a plasma wave receiver system onboard a spacecraft. The objective of the miniaturization is to realize plasma wave observations with high spatial resolutions. By miniaturizing the plasma wave receiver system, we can distribute a lot of plasma wave receivers in a target area. The miniaturization of the plasma wave receiver is realized by designing and developing an analog ASIC chip. The conventional plasma wave receiver consists of commercial discrete devices. However, the ASIC is the special device, which is dedicated only to plasma wave receivers. By using the ASIC of the plasma wave receiver, we developed the smallest plasma wave receiver in the world. Furthermore, we also succeeded in developing a small sensor probe using the ASIC of the plasma wave receiver. The sensor probe carries a electric field sensor made of the CFRP, a small communication wireless device as well as the ASIC. The sensor probe has the capabity to realize multiple point observations in space.
- 科学研究費補助金/基盤研究(B), Apr. 2011 - Mar. 2015, Principal investigatorCompetitive research funding
- 戦略的創造研究推進事業 チーム型研究CREST, Oct. 2007 - Mar. 2012, Principal investigatorCREST「惑星間航行システム開発に向けた大規模シミュレーション研究とマルチスケール粒子法の開発」Competitive research funding
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kyoto University, 2008 - 2010Study on formation process of radiation belts through relativistic acceleration of electrons by whistler-mode wavesChorus emissions are electromagnetic waves with rising-tone frequencies observed in the Earth's magnetosphere. Computer simulations of the wave-particle interaction show that waves grow to form coherent large amplitude waves, causing electron precipitation to the atmosphere. A fraction of the resonant electrons are accelerated to relativistic energy in a short time scale of a few hours. Generation of chorus emissions is a key process of radiation belt formation.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Kyoto University, 2007 - 2010Study on the monitor system for space electromagnetic environmentWe succeeded in developing the very small plasma wave receiver chip using the analogue ASIC. The very small plasma wave receiver chip is the essential component in a sensor node which the Monitor system for space electromagnetic environment (MSEE) consists of. Using this chip, we developed the business card size waveform capture receiver. We also succeeded in developing the small electromagnetic sensors with high sensitivities, which are installed to the MSEE sensor node. Furthermore, we developed the computer simulation code, which can calculate microscopic plasma processes under the spatial anisotropy.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kyoto University, 2006 - 2008Numerical analysis of plasma interference of spacecraft equipped with advanced ion engine by using space environment simulatorプラズマ粒子シミュレーションをベースとした宇宙環境シミュレータを応用し、イオンエンジンプラズマ干渉解析用数値シミュレータ開発を行った。また、それを用いて、イオンエンジン近傍のイオンビームの中和電子ダイナミクスとそのパラメータ依存およびイオンビームと電子の相互作用に関する計算機シミュレーション解析を行い、次世代イオンエンジン搭載宇宙機のプラズマ干渉に関する基礎的な知見を得ることが出来た。
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kyoto University, 2005 - 2007Generation of chorus emissions and acceleration of relativistic electrons associated with magnetic stormsWhistler-mode chorus waves are eletromagnetic emissions that have been observed by spacecraft in the magmetospheres of Earth, Jupiter, Saturn, and Uranus, with frequencies in the range 0.05-0.8 Ω, where Ωis the local electron gyrofrequency. At Earth chorus emissions have also been recorded on the ground Chorus emissions am observed at the time of magnetic field disturbance such as magnetic storms and suhstorms. Chorus waves comprise discrete emissions of short duration (<10-1sec), with frequency typically increasing in time (rising tones), and, when connected to an audio amplifier, sound like bird song at dawn or chirping crickets. Theoretical and modeling studies and observational evidence have established electron acceleration by gyroresonant wave-particle interaction with chorus waves as a key mechanism for generating relativistic (>1 MeV) electrons in the Earth's outer radiation belt during geomagnetically disturbed periods. After nearly four decades of chorus wave observations and numerical studies, only recently have computer simulations been performed that successfully model the generation of chorus emissions with a rising tone. We have found that in the simulation of chorus generation, some resonant electrons are rapidly energized by the processes of relativistic turning acceleration (RTA) and ultra-relativistic acceleration (URA). RTA and URA are particular forms of nonlinear wave trapping of resonant electrons by coherent whistler-mode waves and constitute viable mechanisms for the generation of relativistic electrons in the radiation belts of magnetized planets. The computer simulations reveal that nonlinear wave growth due to the rising tone is the key ingredient in the generation of chorus waves.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), KYOTO UNIVERSITY, 2003 - 2006Study on the advanced electric field measurement system in space plasmas1.Development of the low noise preamplifier : Since we need to detect plasma waves with very low signal levels in the order of a few nV/m/sqrt(Hz), the development of the very low noise preamplifier is important. Especially, in the next generation, we have a plan to observe the thermal fluctuation signals of the vicinity plasmas in order to know the local plasma parameters such as densities and temperatures. We succeeded in developing the very low noise preamplifier with the wide frequency range up to 10MHz. 2.Light-weight carbon fiber antenna : The carbon fiber antenna is the most plausible electric field antenna in the next mission as the electric field sensor extending to the spin axis direction. Since it is made of winding carbon fibers, we worried about the effect of the inductance in the high frequency range. We conducted the field tests for the carbon fiber antennas and confirmed the efficiency is high enough to be used in the space mission. 3.Design of the onboard antenna impedance measurement system : We designed the sophisticated onboard measurement system of electric field sensors based on the coherent detection method. It realizes the measurement of antenna impedance with good S/N ratio. 4.Computer experiments on antenna impedance : We developed 3-dimensional simulation program which can handle the realistic spacecraft shape and antennas under realistic plasma conditions such as densities and temperatures. It also has the capability to treat the dynamics of photo electrons. We investigated the effects of the vicinity plasma conditions to the antenna impedance. 5.Advance and light weight electric field receiver : We attempted to integrate the analog parts of the typical plasma wave receiver system into one-chip device by using the ASIC technology. The developed chip was tested inside the electromagnetic shield chamber and confirmed its functions.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), KYOTO UNIVERSITY, 2003 - 2005Study on ion-wave-plasmas interactions in space plasmas via spacecraft observations and computer experiments-Breakthrough of the magnetospheric physicsWe conducted the fundamental research to make a breakthrough in the study on space plasma physics and magnetospheric physics via spacecraft observations and computer experiments. In spacecraft observations, we always meet the difficulty that we cannot separate the time variation and spatial variation in the observation data. In order to resolve this problem, the simultaneous observations via multiple spacecraft are essential. Since the requirements on weight and size of onboard instruments are very strict in the mission design of multiple spacecraft, we need to miniaturize our instruments. A typical plasma wave receiver system has more analogue parts than other instruments. Therefore, we attempted to realize the analogue parts of a plasma wave receiver system inside a one-chip LSI using the analogue ASIC technology. We design the first stage differential amplifier, low pass filter, and main amplifier with common mode feedback loops, which are stabilize the functions of each amplifier. Since the upper limit frequency of 100kHz is very low, it is impossible to realize the low pass filter using capacitance and inductance inside a analogue ASIC, we designed the gm-C filter, which make use of the conductance of FET inside the ASIC. We also conducted the layout of the connection pattern inside the ASIC chip and submitted the design to the manufacturer. We conducted the function tests and characteristic tests using the manufactured chips. The results will be reflected to the next design. In the computer experiments, we conducted the antenna response in plasmas using the 3-D model. The characteristics of antennas in plasmas as electric field sensors are very complicated. They are strongly depend on the vicinity plasma parameters, plasma sheath, and photo electrons. We established the simulation program for applying to this subject and examined the antenna response using the various plasma conditions.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), KYOTO UNIVERSITY, 2001 - 2003STUDY OF ELECTROMAGNETIC RADIATION FROM ELECTROSTATIC' SOLITARY WAVES IN SPACE PLASMASWe have developed a new method to realize an efficient absorbing boundary for ele'ctro hagnetic particle simulations with a minimal size of the damping region. We have also developed a new algorithm of the charge conservation method for current density calculation, which substantially reduced the computation. We have demonstrated existence of higher harmonics of Langmuir waves enhanced by an electron beam by a newly developed Vlasov code. In an open system with the absorbing boundaries, we traced a long time and long distance evolution of the electron beam instability, showing formation of electrostatic solitary waves and their coupling with oblique whistler waves and lower, hybrid waves, which are localized in the region close to the electron beam generation region. In the two dimensional system, we find the electrostatic solitary waves are accompanied by electromagnetic components due to the localized current driven by the ExB drift associated with the perpendicular electric field of two-dimensional electrostatic potentials. We found an electron beam formation through Buneman instability driven by an induced electric field in the boundary layers of the magnetosphere. The structure and characteristics of electrostatic waves were analyzed theoretically, and the analysis was also extended to a three dimensional model. We obtained the necessary conditions for existence of isolated three-dimensional potentials.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kyoto University, 2000 - 2002Study on antenna characteristics for wave observation including kinetic effects of space plasmaThe objectives of the current study is to acquire the quantitative understanding of antenna characteristics in a magnetized space plasma by performing three-dimensional electromagnetic PIC simulations, which will be helpful designing the antenna onboard the future scientific satellite. We first examined the plasma sheath effect to the antenna impedance. We found that the sheath effect on the antenna impedance become weak when the radius of ion sheath formed around the antenna in the isothermal plasma becomes large. Next, we studied a case in which photo-electrons are emitted from the antenna surface. It is found that antenna impedance is affected at the frequency corresponding to the high density of photo-electrons in the vicinity of antenna. We finally examined a hot plasma case and found that the resonance at the plasma frequency becomes less sharp. Another important factor in the antenna characteristics is the effective length which is related to the current distribution along the antenna. In the receiving mode of antenna, however, the current distribution depends on the load impedance attached to the antenna and therefore the effective length may be modified. We will examine the dependency of the effective length on the load impedance as well as the plasma environment including plasma sheath, photo-electron emission, and finite temperature of plasma by performing EM-PIC simulations.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Kyoto University, 2000 - 2002Study on ion-wave-electron interactions in space plasmas via spacecraft observations and computer experiments -Breakthrough of the magnetospheric physics-In the present study, the main objective is to study the ion-wave-electron coupling in space plasmas based on the development of new observation system, data analyses of spacecraft observations and computer experiments. The representative achievements are as follows. In the view point of spacecraft observation technique, the multiple observations via a fleet of spacecraft are important in order to study ion-wave-electron coupling. Therefore, the development of light-weight plasma wave observation system is essential for future space missions. We succeeded in developing the light-weight receiver using the digital technologies and onboard software technique. The developed plasma wave receiver system was onboard SS-520-2 rocket and it functioned perfectly during the flight. This receiver system I provides a typical model of plasma wave receiver system for future space missions. We also developed the wave-particle correlator, which realizes the direct calculation of correlation between observed plasma waves and particles. We examined its capability and characteristics using computer experiments and designed it on one FPGA chip. In the spacecraft data analyses, we found a proof that the whistler mode waves trigger the dayside magnetic reconnection. Since whistler-mode waves are related to electron dynamics, we can show the link of whistler mode waves as microscopic phenomena with the magnetic reconnection as the macroscopic phenomena. In the computer experiments, we focused on electron/ion beam instabilities and their nonlinear evolutions. Based on many runs of computer experiments, we showed the parametric dependence of their nonlinear evolutions.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B)., KYOTO UNIVERSITY, 1998 - 2000STUDY ON FORMATION PROCESSES OF ELECTROSTATIC SOLITARY WAVES IN SPACE PLASMASAnalyzing the data by the Geotail spacecraft, we found that electrostatic solitary waves (ESW) are carried by high energy electron fluxes along the ambient magnetic field, which agree with the ESW formation model postulated from the simulations. Through statistical analysis of ESW waveforms on many orbits of the Geotail spacecraft in the magnetotail, we found that the generation regions of ESW are located near the neutral points. We performed a 2D particle simulation of magnetic reconnection, and we found that there exist acceleration processes of electrons near the reconnection points. We performed 2D simulations of the bump-on-tail instability to find that 1D solitary potentials are formed after nonlinear evolution of the instability. In the two-stream instability of electrons in a 2D.periodic system, on the other hand, we found that large amplitude potentials traveling fast along the magnetic field can exist stably through coupling with lower hybrid waves propagating slowly in the oblique direction. We also performed 2D simulations with open boundaries, injecting electron beam from one of the boundaries. We found that the ESW formation process found in the periodic system can also take place at the top portion of the electron beam traveling stably through the unperturbed warm plasma. Through theoretical analysis of the ESW formation process based on the BGK theory, we clarified that coalescence of two ESW is an irreversible process where the kinetic energy of electron holes is converted to the thermal energy of electrons trapped in the potential.
- 日本学術振興会, 科学研究費助成事業, 奨励研究(A), 京都大学, 1998 - 1999宇宙飛翔体アンテナと周辺プラズマとの相互作用に関する3次元計算機実験本研究では、宇宙飛翔体上のアンテナ、それによる電波放射、観測、およびアンテナ周辺プラズマの相互関係を3次元電波粒子コードを用いた計算機実験で定量解析することが目的である。本研究の定量的解析により、実際の宇宙プラズマ空間での電波利用および観測の際に非常に有益になる工学的及び理学的な知見を得ることができる。 本年度は、アンテナ周辺のプラズマシース構造をより細かく解析するためにKEMPOにFDTD法で用いられているサブグリッド法を導入することを試みた。サブグリッド法とは微細なグリッド空間を粗いグリッド空間の一部に設け、局所的に高分解に物理を解き進める手法である。これまで、電磁波を解き進めるFDTD法では用いられてきたが、本手法をプラズマ粒子モデルに応用することを試みた。問題点は、違うグリッドシステムを通過する際の粒子にかかる電磁力の補正法であるが、少なくとも1次元モデルではその解決法を提案することができた。また、一方で、アンテナに高周波の電圧をかけた場合における近傍プラズマシースのダイナミクスを解析した。これまで理論的には電界強度の空間変化によって生じるポンデラモーティブ力によりアンテナ近傍プラズマの非線型応答が予測されていたが、本計算機シミュレーションにより、その基本的な物理を再現することができた。また、アンテナシースを伝搬するシース波動の基礎的な解析も行った。今後、これらの基礎的な研究をもとに、プラズマ中のアンテナ特性をプラズマ運動論を考慮したモデルを用いて解析を行う。計算機実験のグラフィック解析及び講演発表のため、本設備備品費でラップトップコンピュータを購入した。
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), KYOTO UNIVERSITY, 1996 - 1999Study on nonlinear wave dynamics in the magnetosphere via computer experiments and plasma waveform analysisWe have studied the nonlinear wave dynamics observed in the Earth's magnetosphere by using plasma waveform data obtained with the GEOTAIL spacecraft and by performing computer experiments with particle model. The analysis of waveforms enables us to extract the spatial as well as temporal nonlinear variation involved in each phenomenon. In particular, waveform analysis of electron modes observed at boundary layers such as the magnetic reconnection region is important in association of plasma heating, acceleration, and perturbation. The aim of this research project is to solve these microscopic nonlinear wave dynamics by performing computer experiments as well as analyzing the waveform data of GEOTAIL. We also utilized unique method in the statistical study of waveforms such as the pattern recognition as well as the conventional Fourier transformation. We paid our attention to the waveforms of broadband electrostatic noise (BEN), narrow band electrostatic noise (NEN), electron cyclotron harmonic waves (ECH), and amplitude modulated Langmuir waves. By combining the analysis of these waveform and computer experiments, we examined microscopic nonlinear processes in the wave dynamics. In particular, the discovery of the generation mechanism of BEN is very significant in the present research project. We, for the first time, found that BEN is made of electrostatic solitary waves (ESW) which are created by the beam-plasma interaction. By Performing computer experiments, we also revealed that ESW is a nonlinear solution of BGK mode generated by the beam-plasma instability. To statistically analyze ESW, we developed a new method using the bit-patter matching, and succeeded in extracting ESW waveforms automatically. We could clarify the relation between the propagation of ESW and that of electron beams, and the width of ESW and the local Debye length. The statistical analysis shows a good agreement with the results obtained in the computer experiments conducted in the present studies.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for international Scientific Research, KYOTO UNIVERSITY, 1996 - 1997Study of wave-particle interactions in space plasmas (Joint research using multiple spacecraft observations and computer experiments)Due to the launch failure, we missed the CLUSTER spacecraft. However, we succeeded to proceed the collaboration among GEOTAIL,WIND,POLAR,Freja, and AKEBONO spacecraft. We performed the simultaneous observations of the Type III solar radio bursts, and 2 fp emissions by GEOTAIL and WIND and we analyzed the propagation features of the Type III solar radio bursts and the source location of the 2 fp emissions. Further, on the AKR emissions, we showed that its source is located at 21-22 MLT based on the collaboration among GEOTAIL,WIND spacecraft and Ray tracing numerical calculations. The modulated Langmuir waves are observed in the tail, solar wind, and polar regions by GEOTAIL,WIND,and Freja spacecraft, respectively. Many theoretical attempts to explain these amplitude modulations have focused on the nonlinear wave-wave coupling, however, they have not succeeded, yet. Our computer experiments succeeded to reproduce the waveforms of these modulated Langmuir waves and showed that the observed amplitude modulations are the result of the spatial modulation of the Langmuir waves due to the trapping effects without the wave-wave interactions. In the collaboration among AKEBONO,Freja spacecraft and the ray tracing, we found that the source region of the Auroral Hiss is located at 11,000km altitude in the polar region. We examined electron velocity distributions corresponding to the observations of the electrostatic solitary waves (ESW). We found the existence of the high energy electrons streaming in the same direction with the ESW.This result is consistent with the BGK potential model which corresponds to the final stage of electron beam instabilities.
- 日本学術振興会, 科学研究費助成事業, 奨励研究(A), 京都大学, 1995 - 19953次元計算機実験による宇宙飛翔体近傍のプラズマ電磁環境に関する研究本研究の目的は、3次元計算機実験により飛翔体・建造物近傍のプラズマ及び電磁界応答の定量的解析を行なうことであり、これにより、実際の宇宙空間での建造物構築の際に非常に有益になる工学的及び理学的な知見を得ることができる。宇宙飛翔体の具体例としては、1次元に長い導体物システムとみなせるシャトル・テザ-衛星システムとブラックアウト、すなわち、地上との通信途絶が問題になる大気圏再突入宇宙機を考え、いずれも3次元計算機実験により宇宙プラズマとの相互作用について解析を行なった。以下に、研究成果をまとめる。 (1)計算機実験で使用する3次元電磁粒子コードの改良を行い、宇宙飛翔体に相当する物体をモデル空間に導体物として取り込む工夫を施した。 (2)宇宙飛翔体のモデルの一つとしてテザ-衛星系を用い、2次元及び3次元空間を用いてその計算機実験を行なった。 (3)高電位衛星近傍での電子シース形成の時空間発展を3次元的に追うことができ、磁場に垂直方向では密度の高いシース形成が確認された。 (4)テザ-系近傍での電磁界擾乱について調べ、テザ-内の過渡電流によるホイッスラ-波動パケットの励起、衛星近傍での電子-イオンの相対速度差によるビーム不安定性について定量的な解析を行なった。 (5)大気圏再突入宇宙機をモデルとした計算機実験を行ない、ブラックアウト(通信途絶)の再現に成功した。 (6)ブラックアウト時における機体近傍の電磁環境について定量解析を行ない、ブラックアウトの特性について定量解析を行なった。
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for international Scientific Research, KYOTO UNIVERSITY, 1994 - 1995Study of Magnetospheric Plasma Waves by Multiple SatellitesThe present project was planned based on the collaboration among GEOTAIL,WIND,AKEBONO,ULYSSES,Freja, POLAR,and INTERBALL spacecraft. However, due to the delay of the launch schedule of the POLAR and INTERBALL spacecraft, we proceeded the collaboration mainly among the GEOTAIl-WIND,GEOTAIL-ULYSSES,and AKEBONO-Freja spacecraft. The collaboration between the GEOTAIL and ULYSSES focused on the study on the interplanetary shock before launching the WIND spacecraft. The USLYSSES observations on the interplanetary shock near the Jupiter showed the good correlation with them by GEOTAIL near the Earth. On the collaboration between the GEOTAIL and WIND spacecraft, we paid our attention to the 2fp emissions, AKR emissions and Type III solar radio bursts. We successfully detected the source region of the 2fp emissions using the delay time of the observations between GEOTAIL and WIND.Further detailed study is continued using the more datasets. The AKR emissions are observed in the high frequency range beyond 100kHz. It is radiated in the polar region and its generation mechanism is closely related to the geomagnetic activities. We studied the propagation characteristics of the AKR using the GEOTAIL and WIND observations. The 2 point observations provide us the important information on the propagation of the AKR.We found the strong location dependence on the observations of the AKR. we checked the calibration of the receivers onboard the GEOTAIL and WIND spacecraft using the Type III solar radio bursts. We found the good agreement on the calibrated intensities of theirs. The plasma wave activities in the polar region were investigated under the collaboration between the AKEBONO and Freja satellites. We focus on the ion cyclotron waves observed in the polar region and discussed their generation mechanisms using the linear theory based on the observations by these 2 satellites which were located in the different altitudes.
- Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for General Scientific Research (B), KYOTO UNIVERSITY, 1993 - 1995Computer Experiments on wave-particle interaction in the boundary layrs and tail region of the magnetospeherWe have studied nonlinear wave-plasma interaction by performing computer experiments with particle model. Since the GEOTAIL launch, various kinds of plasma wave have been observed in the boundary layrs and tail region of the magnetosphere. In those regions, plasma environment is rather turbulent due to high speed flow such as electron/ion beam, and spatial and temporal variation of the magentic field and plasma density. In such a situation, it is revealed that plasma wave activity is so high that is interaction with the charged particles becomes evident. These phenomena are described with nonlinear differential equations and, in general, they are hard to be solved exacely. In order to study such nonlinear Phenomena, we have performed computer experiments by solving the basic equations in space and time. The following is the major results obtained in the present research. (1) We have examined the generation mechanism of Broadband Electrostatic Noize (BEN) which is frequenctly observed at the boundary layrs by GEOTAIL.Our computer experiments reveal that BEN is due to electrostatic solitary wave generated with electron beam in the boundary layr. (2) According to the wave data obtained with the GEOTAIL spacecraft, we have examined the dependence of beam-plasma instabilities on plasma parameters such as flow velocity and plasma density. (3) We have analyzed the magnetic reconnection with a hybrid simulation in which ions are treated as particles while electrons are fluid. In addition to BEN and reconnection, we studied the generation of electron cyclotron harmonic wave and the amplitude modulation of Langmuir wave. We also examined the wave propagation in a case of a plasmoid encounter at the neutral sheet region.
- 日本学術振興会, 科学研究費助成事業, 奨励研究(A), 京都大学, 1994 - 19943次元計算機実験による再突入宇宙機のブラックアウトに関する研究本研究では、地球往還型宇宙機が地球大気圏に再突入する際に生じるブラックアウト現象(通信途絶現象)の解析を3次元電磁粒子コード(KEMPO3D)で計算機実験を用いて定量的に行った。 まず、局所磁場印加によるブラックアウト回避法に関して必要となる磁場強度の評価と定式化を行なった。これにより放射電波エネルギーのプラズマ層透過率は最大30%程度という結果が得られた。低透過率の主な原因は、印加磁場が3次元ダイポールということが考えられる。磁力線に平行に伝搬する電磁波の一部がプラズマ層を直進透過することができないためである。 次に、電波放射によるプラズマ層のパラメータ計測法の開発と検証を行なった。最高プラズマ周波数に関しては、周波数掃引もしくはパルス波の利用によって推定が可能であることが分かった。次にアンテナからの直接波とプラズマ層による反射波の電界の干渉を機体表面上で計測し、幾何工学的に電波の反射点を推定する手法を提案し、その計算機実験を行った。その結果、プラズマ層の最高プラズマ周波数近傍の周波数をもつ電波により、プラズマ層の中心距離について推定できることが明らかになった。 プラズマ層の幅に関しては、計算機実験により理論反射点と推定反射点との誤差をあらかじめ計算しておき、この情報を基に実際の推定反射点のパターンから理論反射点、すなわちプラズマ層の密度プロファイルを得ることを考案した。 本研究を通じて、再突入宇宙機近傍の電磁環境のような容易に実際に実験を行うことの出来ないプラズマ中の電磁波の定量的解析には、3次元計算機実験が非常に有力な手段となりうることがわかった。
- 日本学術振興会, 科学研究費助成事業, 奨励研究(A), 京都大学, 1993 - 1993宇宙大型建造物と宇宙プラズマの電磁力学的相互作用の研究本研究の目的は、近い将来宇宙空間に構築される宇宙ステーションなどの大型建造物と宇宙プラズマとの間の電磁力学的相互作用について計算機実験の手法を用いて定量的解析を行うことである。 本研究では、大型宇宙建造物の一例としてシャトルテザ-衛星系を採用する。1次元方向に長いテザ-導体系が地球磁場を横切る時に、V×B効果により周辺プラズマとの間に最大5kVの電位差が生じる。これにより、テザ-系近傍ではプラズマの加速加熱、通信計測障害と密接に関係するプラズマ波動励起等の現象が生じると考えられる。特に本研究では、テザ-システムがアクティブになり、定常状態に至る過度状態における高電位衛星近傍の電磁場擾乱に着目した。計算機シミュレーションでは、電離層を想定した磁化プラズマで満たされた2次元空間の中に導電体をおき、その電位をゼロからある高電位にした場合の過度応答について解析を行った。 衛星を周辺プラズマに対して高電位にすると、近傍電子は衛星からの強い電界に加速され衛星周辺に高密度のシースを形成する。このことにより、シース形成時には電子の特性周波数、すなわち、電子プラズマ周波数、及び、高域混成周波数における静電振動が卓越することが予想され、計算機シミュレーションでも確認された。電磁場については、高電位衛星近傍において低域混成周波数付近での擾乱が卓越していた。また、シースから少しはなれたプレシースと呼ばれる領域では電子とイオンの相対速度差による2流体プラズマ不安定性が成長することが計算機シミュレーションより明らかになった。 電磁場の擾乱については、電子のE×Bドリフトによる電流が地球磁場に垂直に過渡的に流れることになり、衛星近傍で擾乱が生じるものと考えられる。また、プラズマ不安定性は衛星の電子加速等に大きな影響を与えるため、それによって衛星の電流電圧特性が制御される可能性がある。これについては検討課題である。
- 科学衛星観測による磁気圏プラズマ波動解析及びその計算機シミュレーションCompetitive research funding
- 宇宙飛翔体と宇宙プラズマの電磁力学的相互作用に関する研究Competitive research funding
- Spacecraft observation of Plasma waves in magnetosphereCompetitive research funding
- Study on the Electrodynamic Interaction Between a Spacecraft and Space PlasmaCompetitive research funding