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NAKASHIMA Ryosuke
Graduate School of System Informatics / Department of System Informatics
Assistant Professor

Researcher basic information

■ Research Keyword
  • Physics of the Earth's interior
  • Geomagnetism
  • Geophysical fluid dynamics
■ Research Areas
  • Natural sciences / Solid earth science
  • Natural sciences / Space and planetary science
  • Natural sciences / Atmospheric and hydrospheric science
■ Committee History
  • Sep. 2026 - Present, 第41回数値流体力学シンポジウム実行委員会 委員
  • Apr. 2025 - Nov. 2025, 地球電磁気・地球惑星圏学会 2025年秋季年会 LOC, Web・広報担当、IT担当

Research activity information

■ Award
  • Nov. 2021 SGEPSS, SGEPSS Paper Award, A candidate secular variation model for IGRF-13 based on MHD dynamo simulation and 4DEnVar data assimilation
    Takuto MinamiShin’ya NakanoVincent LesurFutoshi TakahashiMasaki MatsushimaHisayoshi ShimizuRyosuke, NakashimaHinami TaniguchiHiroaki Toh
    Japan society
    IRI

  • Jul. 2016 Japan Geoscience Union, JpGU 2016 Outstading Student Presentation Award, The empirical mode analysis of the decadal variations in the geomagnetic Gauss coefficients
    Ryosuke Nakashima
    Japan society
    IRI

■ Paper
  • Kageyama Akira, Nakashima Ryosuke, Nakato Komei
    An hourglass is known to become slightly heavier while the sand is falling. We quantitatively reproduced this minute weight change through numerical simulation. By treating the hourglass as a mechanical system of coupled variable-mass objects, we find that two effects contribute equally to the weight variation: the linear change in the thickness of the sand layers and the progressive shortening of the free-fall distance of the sand grains. Based on this analysis, we developed a discrete element simulation using the soft-sphere approach. In this model, sand grains fall at a constant rate and accumulate into multiple vertical piles. The simulation, implemented in Processing, can be run on a standard notebook PC.
    Japan Society for Simulation Technology, 2026, Transaction of the Japan Society for Simulation Technology, 18(1) (1), 1 - 10, Japanese
    [Refereed]

  • Kensuke Shobuzako, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima, Shujiro Fujioka, Mitsuteru Asai
    Elsevier BV, May 2025, Results in Applied Mathematics, 26, 100594
    [Refereed]
    Scientific journal

  • Ryosuke Nakashima, Shigeo Yoshida
    Informa UK Limited, Aug. 2024, Geophysical & Astrophysical Fluid Dynamics, 118(5-6) (5-6), 387 - 440
    [Refereed]
    Scientific journal

  • Takuto Minami, Shin’ya Nakano, Vincent Lesur, Futoshi Takahashi, Masaki Matsushima, Hisayoshi Shimizu, Ryosuke Nakashima, Hinami Taniguchi, Hiroaki Toh
    Abstract We have submitted a secular variation (SV) candidate model for the thirteenth generation of International Geomagnetic Reference Field model (IGRF-13) using a data assimilation scheme and a magnetohydrodynamic (MHD) dynamo simulation code. This is the first contribution to the IGRF community from research groups in Japan. A geomagnetic field model derived from magnetic observatory hourly means, and CHAMP and Swarm-A satellite data, has been used as input data to the assimilation scheme. We adopt an ensemble-based assimilation scheme, called four-dimensional ensemble-based variational method (4DEnVar), which linearizes outputs of MHD dynamo simulation with respect to the deviation from a dynamo state vector at an initial condition. The data vector for the assimilation consists of the poloidal scalar potential of the geomagnetic field at the core surface and flow velocity field slightly below the core surface. Dimensionless time of numerical geodynamo is adjusted to the actual time by comparison of secular variation time scales. For SV prediction, we first generate an ensemble of dynamo simulation results from a free dynamo run. We then assimilate the ensemble to the data with a 10-year assimilation window through iterations, and finally forecast future SV by the weighted sum of the future extension parts of the ensemble members. Hindcast of the method for the assimilation window from 2004.50 to 2014.25 confirms that the linear approximation holds for 10-year assimilation window with our iterative ensemble renewal method. We demonstrate that the forecast performance of our data assimilation and forecast scheme is comparable with that of IGRF-12 by comparing data misfits 4.5 years after the release epoch. For estimation of our IGRF-13SV candidate model, we set assimilation window from 2009.50 to 2019.50. We generate our final SV candidate model by linear fitting for the weighted sum of the ensemble MHD dynamo simulation members from 2019.50 to 2025.00. We derive errors of our SV candidate model by one standard deviation of SV histograms based on all the ensemble members.
    Springer Science and Business Media LLC, Sep. 2020, Earth, Planets and Space, 72(1) (1), English, International magazine, Co-authored internationally
    [Refereed]
    Scientific journal

■ MISC
  • Haruto Nakahata, Ryosuke Nakashima, Akira Kageyama
    Aug. 2026, 第53回 可視化情報シンポジウム 講演論文集, Japanese

  • Yushiro Urano, Ryosuke Nakashima, Akira Kageyama
    Aug. 2026, 第53回 可視化情報シンポジウム 講演論文集, Japanese

  • 最小二乗SPH法の打切り誤差に基づく古典的SPH法の離散化誤差の検証—Verification of the discretization error of classical SPH models based on the truncation error of the least squares SPH method
    菖蒲迫 健介, 吉田 茂生, 川田 佳史, 中島 涼輔, 藤岡 秀二郎, 浅井 光輝
    東京 : 日本計算工学会, Jun. 2025, 計算工学講演会論文集 = Proceedings of the Conference on Computational Engineering and Science / 日本計算工学会 編, 30, 824 - 829, Japanese

  • 最小二乗法を用いたSPH法の高精度化について—A high-accuracy SPH method using the least-squares method
    菖蒲迫 健介, 吉田 茂生, 浅井 光輝, 川田 佳史, 中島 涼輔, 藤岡 秀二郎
    東京 : 日本計算工学会, Jun. 2024, 計算工学講演会論文集 = Proceedings of the Conference on Computational Engineering and Science / 日本計算工学会 編, 29, 809 - 814, Japanese

  • Nakashima Ryosuke
    Feb. 2020, Doctoral Thesis (Kyushu University), English
    Others

  • 中島 涼輔
    京都大学 大学院理学研究科 附属地磁気世界資料解析センター, Jan. 2019, 地磁気世界資料解析センター ニュース, (173) (173), Japanese
    Others

■ Lectures, oral presentations, etc.
  • Visualization Analysis of Reversal-like Events in a Regular Tetrahedral MHD Dynamo Model
    Haruto Nakahata, Ryosuke Nakashima, Akira Kageyama
    第53回 可視化情報シンポジウム, Aug. 2026, Japanese, Ishikawa, Japan, Domestic conference
    Oral presentation

  • Visualization of 3D Fluid Simulations Using Mirrors
    Yushiro Urano, Ryosuke Nakashima, Akira Kageyama
    第53回 可視化情報シンポジウム, Aug. 2026, Japanese, Ishikawa, Japan, Domestic conference
    Oral presentation

  • Can quasi-modes in a stratified layer at the top of the Earth's core be observed in geomagnetic fluctuations?
    Ryosuke Nakashima
    JpGU-AGU Joint Meeting 2026, May 2026, English, Chiba, Japan, International conference
    Poster presentation

  • Reversal-like Events in a Regular Tetrahedral MHD Dynamo Model
    Haruto Nakahata, Ryosuke Nakashima, Akira Kageyama
    JpGU-AGU Joint Meeting 2026, May 2026, English, Chiba, Japan, International conference
    Poster presentation

  • 2次元可視化ライブラリ slice-svg 向けブラウザビューアの開発
    福本 晃大, 中島 涼輔, 陰山 聡
    「⾒る可視化」から「調べる可視化」、「⾒せる可視化」へ 先進的可視化表現法とデータ科学の研究会 (VR2025), Dec. 2025, Japanese, 岐阜, Japan
    Oral presentation

  • 傾斜⽴⽅体容器中の熱対流とその可視化
    高井 飛翔, 中島 涼輔, 陰山 聡
    「⾒る可視化」から「調べる可視化」、「⾒せる可視化」へ 先進的可視化表現法とデータ科学の研究会 (VR2025), Dec. 2025, Japanese, 岐阜, Japan
    Oral presentation

  • 回転球面上の 2 次元非圧縮 MHD 波の quasi-mode
    中島 涼輔
    非線形プラズマ科学研究会 2025, Dec. 2025, Japanese, 福岡, Japan
    Oral presentation

  • Verification of the discretization error of classical SPH models based on the truncation error of the least squares SPH method
    Kensuke Shobuzako, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima, Shujiro Fujioka, Mistuteru Asai
    第30回計算工学講演会, Jun. 2025, Japanese, Japan, Domestic conference
    Oral presentation

  • Verification of the Equation of the Flight Distance of a Sand Particle over Wind Ripples in the Nishimori Model by using Numerical Analysis
    Reiji Terada, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima, Kensuke Shobuzako
    Japan Geoscience Union Meeting 2025, May 2025, Japanese, Chiba, Japan, Domestic conference
    Poster presentation

  • Linear stability analysis of Boussinesq convection with explicit methods and its verification using a high-precision particle scheme
    Kensuke Shobuzako, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima
    Japan Geoscience Union Meeting 2025, May 2025, Japanese, Chiba, Japan, Domestic conference
    Oral presentation

  • 木星内部安定成層の MAC 波
    中島涼輔
    地球流体セミナー 分科会, Mar. 2025, Japanese, 北海道 支笏湖, Japan
    Others

  • 回転球面上の2次元非圧縮MHD波の波線理論的アプローチ
    中島 涼輔
    非線形プラズマ科学研究会 2024, Dec. 2024, Japanese, 福岡, Japan
    Oral presentation

  • A ray-theoretical approach to investigate continuous spectra of two-dimensional incompressible MHD waves on a rotating sphere
    Ryosuke Nakashima, Shigeo Yoshida
    8th Asia-Pacific Conference on Plasma Physics, Nov. 2024, English, Malacca, Malaysia, International conference
    [Invited]
    Invited oral presentation

  • Formulation and implementation of the least squares SPH method
    Shobuzako Kensuke, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima
    日本惑星科学会2024年秋季講演会, Sep. 2024, Japanese, Fukuoka, Japan, Domestic conference
    Oral presentation

  • Magnetohydrodynamic waves in a stably stratified region of Jupiter’s interior
    Ryosuke Nakashima, Kumiko Hori
    日本惑星科学会2024年秋季講演会, Sep. 2024, Japanese, Fukuoka, Japan, Domestic conference
    Poster presentation

  • A ray-theoretical approach to investigate two-dimensional MHD waves in a stably stratified layer
    Ryosuke Nakashima, Shigeo Yoshida
    The 18th Symposium of SEDI (Study of the Earth’s Deep Interior), Jun. 2024, English, Great Barrington, MA, United States, International conference
    Poster presentation

  • 最小二乗法を用いたSPH法の高精度化について
    菖蒲迫 健介, 吉田 茂生, 浅井 光輝, 川田 佳史, 中島 涼輔, 藤岡 秀二郎
    第29回計算工学講演会, Jun. 2024, Japanese, 神戸, Japan, Domestic conference
    Oral presentation

  • High accuracy particle method for simulating planetary interiors and its numerical stability analysis
    Shobuzako Kensuke, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima
    Japan Geoscience Union Meeting 2024, May 2024, Japanese, Chiba, Japan, Domestic conference
    Oral presentation

  • quasi modes in inviscid parallel shear flows
    Ryosuke Nakashima
    Japan Geoscience Union Meeting 2024, May 2024, Japanese, Chiba, Japan, Domestic conference
    Poster presentation

  • Development of weakly-compressible SPH method for simulating planetary mantle convection
    Shobuzako Kensuke, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima
    日本惑星科学会2023年秋季講演会, Oct. 2023, Japanese, Hiroshima, Japan, Domestic conference
    Poster presentation

  • Revisit of the stability of inviscid horizontal shear flows with the method of spectral deformation
    Ryosuke Nakashima
    Japan Geoscience Union Meeting 2023, May 2023, Japanese, Chiba, Japan, Domestic conference
    Poster presentation

  • Improving the DISPH method for simulating planetary core formation
    Shobuzako Kensuke, Shigeo Yoshida, Yoshifumi Kawada, Ryosuke Nakashima
    Japan Geoscience Union Meeting 2022, Jun. 2022, Japanese, Chiba / online, Japan, Domestic conference
    Poster presentation

  • Two-dimensional ideal MHD waves over a rotating sphere with continuous spectra of slow magnetic Rossby and Alfvén waves
    Ryosuke Nakashima, Shigeo Yoshida
    Japan Geoscience Union Meeting 2022, Jun. 2022, Japanese, Chiba / online, Japan, Domestic conference
    Poster presentation

  • Two-dimensional ideal MHD waves and the continuous Alfvén spectrum on a rotating sphere with a background toroidal magnetic field
    Ryosuke Nakashima, Shigeo Yoshida
    Japan Geoscience Union Meeting 2021, Jun. 2021, Japanese, online, Japan, Domestic conference
    Poster presentation

  • 連続モードの出現に着目した2次元回転球面上の磁気流体波動の解析
    中島 涼輔
    GFDオンラインセミナー 第3回, Dec. 2020, Japanese, オンライン, Japan
    Oral presentation

  • Contribution to IGRF-13 from Japan: A secular variation model using a numerical dynamo model and 4DEnVar data assimilation
    Takuto Minami, Shin ya Nakano, Futoshi Takahashi, Masaki Matsushima, Ryosuke Nakashima, Hisayoshi Shimizu, Hinami Taniguchi, Hiroaki Toh
    JpGU-AGU Joint Meeting 2020:Virtual, Jul. 2020, English, online, Japan, Domestic conference
    Oral presentation

  • Forecasts of geomagnetic secular variation using core surface flow models (2)
    Masaki Matsushima, Hisayoshi Shimizu, Futoshi Takahashi, Takuto Minami, Shin'ya Nakano, Ryosuke Nakashima, Hinami Taniguchi, Hiroaki Toh
    JpGU-AGU Joint Meeting 2020:Virtual, Jul. 2020, Japanese, online, Japan, Domestic conference
    Poster presentation

  • Inferring geomagnetic secular variation using MHD/kinematic dynamo modeling with data assimilation
    Futoshi Takahashi, Shin'ya Nakano, Takuto Minami, Hinami Taniguchi, Ryosuke Nakashima, Masaki Matsushima, Hisayoshi Shimizu, Hiroaki Toh
    JpGU-AGU Joint Meeting 2020:Virtual, Jul. 2020, English, online, Japan, Domestic conference
    Poster presentation

  • Shallow water MHD waves trapped in the polar regions on a rotating sphere with an imposed azimuthal magnetic field
    Ryosuke Nakashima, Shigeo Yoshida
    JpGU-AGU Joint Meeting 2020:Virtual, Jul. 2020, Japanese, online, Japan, Domestic conference
    Poster presentation

  • Shallow water MHD waves trapped near the poles in a stably stratified outermost Earth's core
    Ryosuke Nakashima, Shigeo Yoshida
    JpGU-AGU Joint Meeting 2020:Virtual, Jul. 2020, English, online, Japan, Domestic conference
    Poster presentation

  • Shallow water MHD waves trapped in the polar regions on a rotating sphere with an imposed azimuthal magnetic field
    Ryosuke Nakashima, Shigeo Yoshida
    146th SGEPSS Fall Meeting （SGEPSS Fall Meeting 2019）, Oct. 2019, Japanese, Kumamoto, Japan, Domestic conference
    Poster presentation

  • Two-dimensional or shallow water MHD waves on a rotating sphere with an imposed azimuthal magnetic field
    Ryosuke Nakashima, Shigeo Yoshida
    Japan Geoscience Union Meeting 2019, May 2019, Japanese, Chiba, Japan, Domestic conference
    Poster presentation

  • Effects of an azimuthal background magnetic field on slow waves in a stably stratified outermost Earth's core
    Ryosuke Nakashima
    Workshop: Forecasting the geomagnetic secular variation with data assimilation, Sep. 2018, English, Paris, France, International conference
    Oral presentation

  • The effect of an azimuthal background magnetic field on waves in a stably stratified layer at the top of the Earth's outer core
    Ryosuke Nakashima, Shigeo Yoshida
    Japan Geoscience Union Meeting 2018, May 2018, English, Chiba, Japan, Domestic conference
    Poster presentation

  • 地球外核最上部の安定成層における流体波動 〜地磁気永年変動との比較に向けて〜
    中島 涼輔
    第49回 地磁気・古地磁気・岩石磁気 夏の学校, Sep. 2017, Japanese, 福岡, Japan
    Oral presentation

  • Equatorial waves modified by the presence of a toroidal magnetic field within the stably stratified layer at the top of the Earth’s outer core
    Ryosuke Nakashima, Shigeo Yoshida
    JpGU-AGU Joint Meeting 2017, May 2017, Japanese, Chiba, Japan, Domestic conference
    Poster presentation

  • Alfvén波の固有モード 〜単純かと思いきや、ちょっと困った〜
    中島涼輔
    地球流体セミナー 分科会, Aug. 2016, Japanese, 北海道 支笏湖, Japan
    Others

  • The empirical mode analysis of the decadal variations in the geomagnetic Gauss coefficients
    Ryosuke Nakashima, Shigeo Yoshida
    Japan Geoscience Union Meeting 2016, May 2016, Japanese, Chiba, Japan, Domestic conference
    Poster presentation

  • The boundary mode of the axially symmetric MAC wave in the stratified layer at the top of the Earth’s outer core
    Ryosuke Nakashima, Shigeo Yoshida
    Japan Symposium of Study of the Earth’s Deep Interior 2015, Sep. 2015, English, Tokyo, Japan, Domestic conference
    Poster presentation

  • The boundary mode of axially symmetric MAC waves can exist in the stratified layer at the top of the Earth's outer core
    Ryosuke Nakashima, Shigeo Yoshida
    Japan Geoscience Union Meeting 2015, May 2015, Japanese, Chiba, Japan, Domestic conference
    Poster presentation

■ Affiliated Academic Society
  • The Japan Society of Fluid Mechanics
    Apr. 2026 - Present
    IRI

  • Society of Geomagnetism and Earth, Planetary and Space Sciences
    May 2025 - Present
    IRI

  • The Japanese Society for Planetary Sclences
    Jul. 2024 - Present
    IRI

  • Division of Plasma Physics Association of Asia Pacific Physical Societies
    May 2024 - Present
    IRI

  • Japan Geoscience Union
    Feb. 2015 - Present
    IRI

■ Works
■ Research Themes
  • 地球外核最上部のダイナミクス：波が駆動する大規模地磁気変動の観測可能性の検証
    中島 涼輔
    日本学術振興会, 科学研究費助成事業, 若手研究, 九州大学, Apr. 2025 - Mar. 2029, Principal investigator

  • 惑星内部ダイナモから表層大気雲対流までを包括した木星変動現象の解明
    堀 久美子, 中島 健介, 杉山 耕一朗, 中島 涼輔, 竹広 真一
    日本学術振興会, 科学研究費助成事業, 基盤研究(B), 神戸大学, Apr. 2024 - Mar. 2028, Coinvestigator

  • 地球外核最上部を伝播する磁気流体波の連続スペクトル減衰とその数値シミュレ ーション
    中島 涼輔, 大貫 陽平, 堀 久美子
    九州大学 応用力学研究所 共同利用・共同研究, Apr. 2026 - Mar. 2027, Principal investigator

  • 地球外核最上部のダイナミクス：波動による地球内部東西磁場強度推定の試み
    吉田 茂生, 中島 涼輔
    日本学術振興会, 科学研究費助成事業, 基盤研究(C), 九州大学, Apr. 2024 - Mar. 2027, Coinvestigator

  • 地球外核最上部を伝播する磁気流体波の連続スペクトル減衰
    中島 涼輔, 大貫 陽平
    九州大学 応用力学研究所 共同利用・共同研究, Apr. 2025 - Mar. 2026, Principal investigator

  • 地球外核最上部におけるアルフベン波連続スペクトル
    中島 涼輔, 堀 久美子, 吉田 茂生
    核融合科学研究所 一般共同研究, Apr. 2024 - Mar. 2025, Principal investigator

  • 地球外核最上部の安定成層内の流体波動に関する研究
    九州大学 博士後期課程奨学金, Jul. 2017 - Mar. 2020

■ Social Contribution Activities
■ Others
  • Peer review (2025)
    Earth, Planets and Space (1) / Geophysical Research Letters (1) / Mechanical Engineering Advances (1)

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