Updated on 2023/09/11

写真a

 
UMEDA, Takayuki
 
Organization
Institute for Space-Earth Environmental Research Center for Integrated Data Science Associate professor
Graduate School
Graduate School of Engineering
Title
Associate professor
Contact information
メールアドレス
Homepage
http://www.isee.nagoya-u.ac.jp/~umeda/
External link

Degree 1

  1. Doctor of Informatics （ 2004.3   Kyoto University ） 

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Research Interests 5

  1. Geoscience

  2. Electromagnetic fields

  3. High performance Computing

  4. Plasma science

  5. Computer simulation

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Research Areas 4

  1. Informatics / Computational science  / Computational Science

  2. Energy Engineering / Fundamental plasma  / Plasma Science

  3. Natural Science / Space and planetary sciences  / Upper Atmospheric Physics

  4. Informatics / High performance computing  / High-performance Computing

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Current Research Project and SDGs 3

  1. Global kinetic simulation of Geospace

  2. First-principle particle simulation of collsionless shocks

  3. Developments and applications of computational electromagnetics

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Research History 2

  1. UCLA-IGPP Postgraduate Researcher

    2004.4 - 2006.3

  2. JSPS Research Fellow

    2001.4 - 2004.3

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    Country：Japan

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Education 3

  1. Kyoto University   Graduate School, Division of Information and Communication   Department of Communications and Computer Engineering

    2001.4 - 2004.3

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    Country： Japan

  2. Kyoto University   Graduate School, Division of Information and Communication   Department of Communications and Computer Engineering

    1999.4 - 2001.3

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    Country： Japan

  3. Kyoto University   Faculty of Engineering   School of Electrical and Electronic Engineering

    1995.4 - 1999.3

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    Country： Japan

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Professional Memberships 4

  1. Society of Geomagnetism and Earth, Planetary and Space Sciences

    2000

  2. Americal Geophysical Union

    2003

  3. Japan Geoscience Union

    2009

  4. IEEE

    2021.2

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Committee Memberships 8

  1. 日本学術振興会   特別研究員等審査委員会専門委員  

    2021.4 - 2022.3   

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    Committee type：Academic society

  2. サイエンティフィック・システム研究会   A64FXシステムアプリ性能検討WG 推進委員  

    2020.11 - 2022.10   

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    Committee type：Other

  3. 高度情報科学技術研究機構   HPCIシステム利用研究課題審査委員会レビュアー  

    2019.10   

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    Committee type：Academic society

  4. サイエンティフィック・システム研究会   メニーコア時代のアプリ性能検討WG 推進委員  

    2017.1 - 2018.12   

  5. 生存圏フォーラム   運営委員  

    2014.6 - 2018.2   

  6. サイエンティフィック・システム研究会   ポストペタアプリ性能WG 推進委員  

    2014.3 - 2016.2   

  7. 京都大学生存圏研究所   KDK共同利用専門委員  

    2012.4   

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    Committee type：Other

  8. サイエンティフィック・システム研究会   マルチコアクラスタ性能WG 推進委員  

    2010.12 - 2013.5   

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Awards 5

  1. 2nd Asia-Pacific Conference on Plasma Physics (AAPPS-DPP2018) Poster Prize

    2018.11   Division of Plasma Physics, Association of Asia Pacific Physical Societies   Non-MHD effects in the nonlinear development of the MHD-scale Rayleigh-Taylor instability

    T. Umeda and Y. Wada

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    Award type：Award from international society, conference, symposium, etc. 

  2. 科学技術分野の文部科学大臣表彰 若手科学者賞

    2015.4   文部科学省   先端的宇宙プラズマ計算機シミュレーション手法の研究

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    Award type：International academic award (Japan or overseas)  Country：Japan

  3. 大林奨励賞

    2012.10   地球電磁気・地球惑星圏学会   計算機シミュレーション手法の開発とその宇宙プラズマ現象への応用

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    Award type：Award from Japanese society, conference, symposium, etc.  Country：Japan

  4. Best Presentations Award for International Conference of Frontiers in Computational Science 2008 Grant Prix

    2008.11   Frontiers in Computational Science 2008 Program Committee   Vlasov code simulation of GEM reconnection challenge

    K. Togano, T. Umeda, and T. Ogino

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    Award type：Award from international society, conference, symposium, etc.  Country：Japan

  5. International Union of Radio Science Young Scientist Award

    2005.10   International Union of Radio Science  

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    Award type：Award from international society, conference, symposium, etc. 

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Papers 106

  1. New Aspects of Energy Conversion in Magnetic Island Dynamics: Particle-in-cell Simulation of Multiple Island Coalescence and MMS Observations Reviewed

    Teh W. -l., Nakamura T. K. M., Zenitani S., Umeda T., Nakamura R.

    ASTROPHYSICAL JOURNAL   Vol. 947 ( 1 )   2023.4

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：Astrophysical Journal  

    Coalescence of multiple magnetic islands is recognized as an effective process to energize particles during magnetic reconnection, while its energy conversion process still remains unclear. Here, a two-dimensional fully kinetic simulation of multiple island coalescence with a small reconnection guide field is studied. In the analysis of energy conversion within a magnetic island, the dot product of V e · j × B = w 1 is a useful quantity to compare with j · E = w 2, since the average work done by the Lorentz force on the circulating particles is negligible in the island and w 2 − w 1 = j · E + V e × B = j · E ′ = w 3 . A bipolar pattern of w 1 is found at a secondary island when the electrons are in circular motion inside the island. Significant energy dynamo (w 3 < 0) resulting from j ∥ E ∥ is found at the secondary island, which has not been reported before, where the parallel electric field E ∥ is highly correlated with w 3. Moreover, significant energy dissipation (w 3 > 0) due to j ⊥ · E ⊥ ′ is seen in the merging region between two coalescing islands. Both types of energy conversions are accompanied by enhancements in j ∥ and the parallel electron temperature T e∥. Three ion-scale magnetic islands (FR1, FR2, and FR3) observed by the Magnetospheric Multiscale spacecraft are compared favorably with the simulated signatures of energy dynamo and dissipation of an evolving secondary island. In particular, FR1 displayed a similar energy dynamo signature as that simulated in an early stage of the secondary island. FR2 and FR3 showed a dominant j ⊥ · E ⊥ ′ energy conversion similar to that obtained in a later stage of the secondary island.

    DOI： 10.3847/1538-4357/acc2bf

    Web of Science

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  2. Spatial and time scaling of coalescing multiple magnetic islands Reviewed

    Nakamura T. K. M., Teh W. -l., Zenitani S., Umeda T., Oka M., Hasegawa H., Veronig A. M., Nakamura R.

    PHYSICS OF PLASMAS   Vol. 30 ( 2 )   2023.2

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：Physics of Plasmas  

    Magnetic reconnection is a key fundamental process in collisionless plasmas, which converts magnetic energy to plasma kinetic energy. Past observation and simulation studies suggested that this process causes an efficient energy conversion through the formation and coalescence of multiple magnetic islands. In this study, based on a large-scale two-dimensional fully kinetic simulations of coalescing multiple islands with a moderate guide magnetic field, we first examined the spatial dimensions of the internal structures of the coalescing islands. The results show that the dimensions of the structures in the directions normal to and along the initial current sheet depend on the initial thickness of the current sheet and the number of coalescing islands. We then found that the horizontal dimension of the structures controls the evolution time scale of the island coalescence process. We further found that when the vertical dimension of the structures, which corresponds to the length of the reconnection X-line in the reconnection outflow direction at the merging point between the two coalescing islands, is sufficiently longer than the ion inertial length, reconnection in the merging current sheet can well mature and both ions and electrons can be effectively heated around the merging X-line. The obtained scaling predicts that such a strong heating by well-matured reconnection in the island coalescence process would be seen in various plasma environments, such as the Earth's magnetotail and solar flares.

    DOI： 10.1063/5.0127107

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  3. Relaxation of the Courant Condition in the Explicit Finite-Difference Time-Domain Method With Higher-Degree Differential Terms Reviewed

    Sekido Harune, Umeda Takayuki

    IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION   Vol. 71 ( 2 ) page： 1630 - 1639   2023.2

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEEE Transactions on Antennas and Propagation  

    A new explicit and nondissipative finite-difference time-domain (FDTD) method in two and three dimensions is proposed for the relaxation of the Courant condition. The third-degree spatial difference terms with second- and fourth-order accuracies are added with coefficients to the time-development equations of FDTD(2,4). Optimal coefficients are obtained by a brute-force search of the dispersion relations, which reduces phase velocity errors but satisfies the numerical stabilities as well. The new method is stable with large Courant numbers, whereas the conventional FDTD methods are unstable. The new method also has smaller numerical errors in the phase velocity than conventional FDTD methods with small Courant numbers.

    DOI： 10.1109/TAP.2023.3234097

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  4. A new integrator for relativistic E-cross-B motion of charged particles Reviewed

    Umeda Takayuki

    JOURNAL OF COMPUTATIONAL PHYSICS   Vol. 472   2023.1

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Journal of Computational Physics  

    A new explicit numerical scheme for integrating the relativistic equations of motion for electrically charged particles is proposed as an alternative to the Boris integrator. It has been known that the original Boris integrator includes a large numerical error in the relativistic motion, although the integrator has been used in particle-in-cell simulations of plasma for a half century. The present integrator approximates the theoretical trajectory of the relativistic E-cross-B motion for a charged particle more accurately than the previous explicit integrators such as the Boris, Vay, and Higuera-Cary ones.

    DOI： 10.1016/j.jcp.2022.111694

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  5. Multicolor reordering for computing moments in particle-in-cell plasma simulations Reviewed

    Umeda Takayuki

    COMPUTER PHYSICS COMMUNICATIONS   Vol. 281   2022.12

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Computer Physics Communications  

    Thread parallelism in the computation of the current density/charge density in particle-in-cell plasma simulations has been performed by using the reduction operation conventionally, which is known to have a larger computational overhead with a larger number of threads. In the present study, two types of multicolor reordering, i.e., loop striding and loop tiling/blocking are introduced for a particle shape function with an arbitrary degree, which is free from the reduction operation. The present performance measurement result suggests that the loop tiling is superior to the loop striding.

    DOI： 10.1016/j.cpc.2022.108499

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  6. High-power laser experiment forming a supercritical collisionless shock in a magnetized uniform plasma at rest Reviewed

    Yamazaki R., Matsukiyo S., Morita T., Tanaka S. J., Umeda T., Aihara K., Edamoto M., Egashira S., Hatsuyama R., Higuchi T., Hihara T., Horie Y., Hoshino M., Ishii A., Ishizaka N., Itadani Y., Izumi T., Kambayashi S., Kakuchi S., Katsuki N., Kawamura R., Kawamura Y., Kisaka S., Kojima T., Konuma A., Kumar R., Minami T., Miyata I, Moritaka T., Murakami Y., Nagashima K., Nakagawa Y., Nishimoto T., Nishioka Y., Ohira Y., Ohnishi N., Ota M., Ozaki N., Sano T., Sakai K., Sei S., Shiota J., Shoji Y., Sugiyama K., Suzuki D., Takagi M., Toda H., Tomita S., Tomiya S., Yoneda H., Takezaki T., Tomita K., Kuramitsu Y., Sakawa Y.

    PHYSICAL REVIEW E   Vol. 105 ( 2 )   2022.2

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1103/PhysRevE.105.025203

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  7. Multi-scale evolution of Kelvin-Helmholtz waves at the Earth's magnetopause during southward IMF periods Reviewed

    Nakamura T. K. M., Blasl K. A., Hasegawa H., Umeda T., Liu Y-H, Peery S. A., Plaschke F., Nakamura R., Holmes J. C., Stawarz J. E., Nystrom W. D.

    PHYSICS OF PLASMAS   Vol. 29 ( 1 )   2022.1

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Physics of Plasmas  

    At the Earth's low-latitude magnetopause, the Kelvin-Helmholtz instability (KHI), driven by the velocity shear between the magnetosheath and magnetosphere, has been frequently observed during northward interplanetary magnetic field (IMF) periods. However, the signatures of the KHI have been much less frequently observed during southward IMF periods, and how the KHI develops under southward IMF has been less explored. Here, we performed a series of realistic 2D and 3D fully kinetic simulations of a KH wave event observed by the Magnetospheric Multiscale (MMS) mission at the dusk-flank magnetopause during southward IMF on September 23, 2017. The simulations demonstrate that the primary KHI bends the magnetopause current layer and excites the Rayleigh-Taylor instability (RTI), leading to penetration of high-density arms into the magnetospheric side. This arm penetration disturbs the structures of the vortex layer and produces intermittent and irregular variations of the surface waves which significantly reduces the observational probability of the periodic KH waves. The simulations further demonstrate that in the non-linear growth phase of the primary KHI, the lower-hybrid drift instability (LHDI) is induced near the edge of the primary vortices and contributes to an efficient plasma mixing across the magnetopause. The signatures of the large-scale surface waves by the KHI/RTI and the small-scale fluctuations by the LHDI are reasonably consistent with the MMS observations. These results indicate that the multi-scale evolution of the magnetopause KH waves and the resulting plasma transport and mixing as seen in the simulations may occur during southward IMF.

    DOI： 10.1063/5.0067391

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  8. Evaluating higher moments in the transverse Kelvin-Helmholtz instability by full kinetic simulation Reviewed

    Umeda T.

    Physics of Plasmas   Vol. 27 ( 3 )   2020.3

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5139442

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  9. Stability of Contact Discontinuities in Electrostatic Hybrid- and Full-Vlasov Simulations Reviewed

    Tsujine Naru, Haruki Takayuki, Umeda Takayuki, Nariyuki Yasuhiro, Sato Masahiro

    PLASMA AND FUSION RESEARCH   Vol. 15   2020.2

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1585/pfr.15.1401002

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  10. Disturbance of the Front Region of Magnetic Reconnection Outflow Jets due to the Lower-Hybrid Drift Instability Reviewed

    Nakamura T. K. M., Umeda T., Nakamura R., Fu H. S., Oka M.

    PHYSICAL REVIEW LETTERS   Vol. 123 ( 23 )   2019.12

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1103/PhysRevLett.123.235101

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  11. Mach number and plasma beta dependence of the ion temperature perpendicular to the external magnetic field in the transition region of perpendicular collisionless shocks Reviewed

    Yamazaki Ryo, Shinoda Ayato, Umeda Takayuki, Matsukiyo Shuichi

    AIP ADVANCES   Vol. 9 ( 12 )   2019.12

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5129067

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  12. Vlasov code simulation of contact discontinuities Reviewed

    Umeda T.

    Physics of Plasmas   Vol. 26 ( 10 )   2019.10

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5100314

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  13. Multi-step Boris rotation schemes for Lorentz force equation of charged particles Reviewed

    Umeda T.

    Computer Physics Communications   Vol. 237   page： 37 - 41   2019.4

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.cpc.2018.11.001

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  14. Full particle-in-cell simulation of the interaction between two plasmas for laboratory experiments on the generation of magnetized collisionless shocks with high-power lasers

    Umeda Takayuki, Yamazaki Ryo, Ohara Yutaka, Ishizaka Natsuki, Kakuchi Shin, Kuramitsu Yasuhiro, Matsukiyo Shuichi, Miyata Itaru, Morita Taichi, Sakawa Youichi, Sano Takayoshi, Sei Shuto, Tanaka Shuta J., Toda Hirohumi, Tomita Sara

    PHYSICS OF PLASMAS   Vol. 26 ( 3 )   2019.3

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5079906

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  15. Magnetosonic/whistler mode turbulence influences on ion dynamics

    Saito S., Nariyuki Y., Umeda T.

    PHYSICS OF PLASMAS   Vol. 25 ( 12 )   2018.12

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5053760

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  16. On the Boris solver in particle-in-cell simulation Reviewed

    Zenitani Seiji, Umeda Takayuki

    PHYSICS OF PLASMAS   Vol. 25 ( 11 )   2018.11

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5051077

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  17. Electromagnetic linear dispersion relation for plasma with a drift across magnetic field revisited Reviewed

    Umeda T., Nakamura T. K. M.

    Physics of Plasmas   Vol. 25 ( 10 )   2018.10

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5050542

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  18. Oblique Ion-Scale Magnetotail Flux Ropes Generated by Secondary Tearing Modes Reviewed

    Teh Wai-Leong, Nakamura Takuma, Nakamura Rumi, Umeda Takayuki

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 123 ( 10 ) page： 8122 - 8130   2018.10

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Journal of Geophysical Research: Space Physics  

    We examine Magnetospheric Multiscale observations of three ion-scale magnetic flux ropes (diameter ~6–9 ion inertial lengths) in the Earth's magnetotail reconnection diffusion region with a small guide field. During the event, the electron reconnection exhaust reversed direction together with the reversal of normal magnetic field component. After that, the three ion-scale flux ropes were observed near the ion diffusion region, in which flat-top distributions were found at the field-aligned electrons (<2 keV). The axis orientation and motion velocity of the flux ropes are determined by minimum variance analysis of the electric field component along the flux rope axis, using single-spacecraft measurements. Results show that the three flux rope axes form 13°, 55°, and 55° to the guide field direction and are mostly tilted toward the direction of the reconnecting field. These results are also validated by multiple-spacecraft analysis methods. It is found that the tilted angles agree reasonably well with the predicted angles for secondary tearing modes, suggesting that these ion-scale flux ropes are likely generated by secondary tearing instabilities as those recently found in the three-dimensional kinetic simulations of turbulent magnetic reconnection.

    DOI： 10.1029/2018JA025775

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  19. Periodic self-reformation of rippled perpendicular collisionless shocks in two dimensions Reviewed

    Umeda Takayuki, Daicho Yuki

    ANNALES GEOPHYSICAE   Vol. 36 ( 4 ) page： 1047 - 1055   2018.8

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Annales Geophysicae  

    Large-scale two-dimensional (2-D) full particle-in-cell (PIC) simulations are carried out for studying periodic self-reformation of a supercritical collisionless perpendicular shock with an Alfvén-Mach number MA ∼ 6. Previous self-consistent one-dimensional (1-D) hybrid and full PIC simulations have demonstrated that the periodic reflection of upstream ions at the shock front is responsible for the formation and vanishing of the shock-foot region on a timescale of the local ion cyclotron period, which was defined as the reformation of span styleCombining double low line"" classCombining double low line"text"(quasi-)perpendicular/span> shocks. The present 2-D full PIC simulations with different ion-to-electron mass ratios show that the dynamics at the shock front is strongly modified by large-amplitude ion-scale fluctuations at the shock overshoot, which are known as ripples. In the run with a small mass ratio, the simultaneous enhancement of the shock magnetic field and the reflected ions take place quasi-periodically, which is identified as the reformation. In the runs with large mass ratios, the simultaneous enhancement of the shock magnetic field and the reflected ions occur randomly in time, and the shock magnetic field is enhanced on a timescale much shorter than the ion cyclotron period. These results indicate a coupling between the shock-front ripples and electromagnetic microinstabilities in the foot region in the runs with large mass ratios.

    DOI： 10.5194/angeo-36-1047-2018

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  20. A three-step Boris integrator for Lorentz force equation of charged particles Reviewed

    Umeda Takayuki

    COMPUTER PHYSICS COMMUNICATIONS   Vol. 228   page： 1-4   2018.7

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.cpc.2018.03.019

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  21. Decay of nonlinear whistler mode waves: 1D versus 2D Reviewed

    Umeda Takayuki, Saito Shinji, Nariyuki Yasuhiro

    PHYSICS OF PLASMAS   Vol. 25 ( 7 )   2018.7

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.5031483

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  22. Performance Evaluation and Optimization of MagnetoHydroDynamic Simulation for Planetary Magnetosphere with Xeon Phi KNL Reviewed

    Fukazawa K., Soga T., Umeda T., Nanri T.

    Advances in Parallel Computing   Vol. 32   page： 178-187   2018.1

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.3233/978-1-61499-843-3-178

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  23. Performance Analysis of CPU and DRAM Power Constrained Systems with Magnetohydrodynamic Simulation Code Reviewed

    Fukazawa Keiichiro, Ueda Masatsugu, Inadomi Yuichi, Aoyagi Mutsumi, Umeda Takayuki, Inoue Koji

    IEEE 20TH INTERNATIONAL CONFERENCE ON HIGH PERFORMANCE COMPUTING AND COMMUNICATIONS / IEEE 16TH INTERNATIONAL CONFERENCE ON SMART CITY / IEEE 4TH INTERNATIONAL CONFERENCE ON DATA SCIENCE AND SYSTEMS (HPCC/SMARTCITY/DSS)     page： 626-631   2018

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1109/HPCC/SmartCity/DSS.2018.00113

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  24. Generation of intermittent ion acoustic waves in whistler-mode turbulence Reviewed

    Saito S., Nariyuki Y., Umeda T.

    PHYSICS OF PLASMAS   Vol. 24 ( 7 )   2017.7

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4990443

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  25. Non-MHD effects in the nonlinear development of the MHD-scale Rayleigh-Taylor instability Reviewed

    Umeda Takayuki, Wada Yasutaka

    PHYSICS OF PLASMAS   Vol. 24 ( 7 )   2017.7

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4991409

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  26. Rapid decay of nonlinear whistler waves in two dimensions: Full particle simulation Reviewed

    Umeda Takayuki, Saito Shinji, Nariyuki Yasuhiro

    PHYSICS OF PLASMAS   Vol. 24 ( 5 )   2017.5

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4982609

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  27. Secondary instabilities in the collisionless Rayleigh-Taylor instability: Full kinetic simulation Reviewed

    T. Umeda, Y. Wada

    Physics of Plasmas   Vol. 23 ( 11 ) page： 112117 (8pp.)   2016.11

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4967859

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  28. Three-dimensional development of front region of plasma jets generated by magnetic reconnection Reviewed

    Nakamura T. K. M., Nakamura R., Baumjohann W., Umeda T., Shinohara I.

    GEOPHYSICAL RESEARCH LETTERS   Vol. 43 ( 16 ) page： 8356-8364   2016.8

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1002/2016GL070215

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  29. Evaluating gyro-viscosity in the Kelvin-Helmholtz instability by kinetic simulations Reviewed

    T. Umeda, N. Yamauchi, Y. Wada, S. Ueno

    Physics of Plasmas   Vol. 23 ( 5 ) page： 054506 (4pp.)   2016.5

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4952632

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  30. Performance comparison of Eulerian kinetic Vlasov code between flat-MPI parallelism and hybrid parallelism on Fujitsu FX100 supercomputer

    Umeda Takayuki, Fukazawa Keiichiro

    PROCEEDINGS OF THE 23RD EUROPEAN MPI USERS' GROUP MEETING (EUROMPI 2016)   Vol. 25-28-September-2016   page： 218-221   2016

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1145/2966884.2966891

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  31. Toward the Generation of Magnetized Collisionless Shocks with High-Power Lasers

    Shoji Yoshitaka, Yamazaki Ryo, Tomita Sara, Kawamura Yushiro, Ohira Yutaka, Tomiya Satoshi, Sakawa Yoichi, Sano Takayoshi, Hara Yukiko, Kondo Sarana, Shimogawara Hiroshi, Matsukiyo Shuichi, Morita Taichi, Tomita Kentaro, Yoneda Hitoki, Nagamine Kazunori, Kuramitsu Yasuhiro, Moritaka Toseo, Ohnishi Naofumi, Umeda Takayuki, Takabe Hideaki

    PLASMA AND FUSION RESEARCH   Vol. 11 ( 2 )   2016

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1585/pfr.11.3401031

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  32. Hybrid Parallelization of Hyper-Dimensional Vlasov Code with OpenMP Loop Collapse Directive Reviewed

    Umeda Takayuki, Fukazawa Keiichiro

    PARALLEL COMPUTING: ON THE ROAD TO EXASCALE   Vol. 27   page： 265 - 274   2016

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：Advances in Parallel Computing  

    Space plasma is a collisionless, multi-scale, and highly nonlinear medium. Computer simulations with the first-principle kinetic equation are essential for space plasma studies. In the present study, a hyper-dimensional Vlasov (collisionless Boltzmann) simulation code, which is a first-principle method for collisionless space plasma, is parallelized with two-level hybrid MPI and OpenMP and is benchmarked on massively-parallel supercomputer systems. The benchmark result shows that the loop "collapse" directive option of the OpenMP reduces threading overhead of multiple loops. It is also shown that the hybrid parallelism with MPI and OpenMP is useful to reduce the communication time of MPI collective communication subroutines.

    DOI： 10.3233/978-1-61499-621-7-265

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  33. Note on one-fluid modeling of low-frequency Alfvenic fluctuations in a solar wind plasma with multi-ion components Reviewed

    Y. Nariyuki, T. Umeda, T. K. Suzuki, T. Hada

    Physics of Plasmas   Vol. 22 ( 12 ) page： 124502 (4pp.)   2015.12

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    DOI： 10.1063/1.4936798

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  34. Nonlinear damping of a finite amplitude whistler wave due to modified two stream instability Reviewed

    S. Saito, T. Umeda, Y. Nariyuki

    Physics of Plasmas   Vol. 22 ( 7 ) page： 072105 (7pp.)   2015.7

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4926523

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  35. A high-resolution global Vlasov simulation of a small dielectric body with a weak intrinsic magnetic field on the K computer Reviewed

    T. Umeda, K. Fukazawa

    Earth, Planets and Space   Vol. 67 ( 1 ) page： 49   2015.4

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    DOI： 10.1186/s40623-015-0216-0

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  36. Performance comparison of open-source parallel sorting with OpenMP

    Umeda Takayuki, Oya Shuhei

    PROCEEDINGS OF 2015 THIRD INTERNATIONAL SYMPOSIUM ON COMPUTING AND NETWORKING (CANDAR)     page： 334-340   2015

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    DOI： 10.1109/CANDAR.2015.25

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  37. Performance tuning of Vlasov code for space plasma on the K computer

    T. Umeda, K. Fukazawa

    AsiaSim 2014, Communications in Computer and Information Science   Vol. 474   page： 127-138   2014.11

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  38. Electron acceleration during the decay of nonlinear whistler waves in low-beta electron-ion plasma Reviewed

    T. Umeda, S. Saito, Y. Nariyuki

    Astrophysical Journal   Vol. 794 ( 1 ) page： 63 (10pp.)   2014.10

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1088/0004-637X/794/1/63

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  39. Ion kinetic effects to nonlinear processes of the Kelvin-Helmholtz instability Reviewed

    T. Umeda, S. Ueno, T. K. M. Nakamura

    Plasma Physics and Controlled Fusion   Vol. 56 ( 7 ) page： 075006 (11pp.)   2014.7

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    DOI： 10.1088/0741-3335/56/7/075006

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  40. Entry of solar-wind ions into the wake of a small body with a magnetic anomaly: A global Vlasov simulation Reviewed

    T. Umeda, Y. Ito

    Planetary and Space Science   Vol. 93-94   page： 35 - 40   2014.4

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.pss.2014.02.002

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  41. Some remarks on the diffusion regions in magnetic reconnection Reviewed

    S. Zenitani, T. Umeda

    Physics of Plasmas   Vol. 21 ( 3 ) page： 034503 (5pp.)   2014.3

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4869717

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  42. Dynamics and microinstabilities at perpendicular collisionless shock: A comparison of large-scale two-dimensional full particle simulations with different ion to electron mass ratio Reviewed

    T. Umeda, Y. Kidani, S. Matsukiyo, R. Yamazaki

    Physics of Plasmas   Vol. 21 ( 2 ) page： 022102 (10pp.)   2014.2

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.4863836

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  43. Performance tuning of Vlasov code for space plasma on the K computer

    Umeda T., Fukazawa K.

    Communications in Computer and Information Science   Vol. 474   page： 127-138   2014.1

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  44. Ion acceleration by parallel propagating nonlinear Alfven wave packets in a radially expanding plasma Reviewed

    Y. Nariyuki, T. Umeda, T. K. Suzuki, T. Hada

    Nonlinear Processes in Geophysics   Vol. 21 ( 1 ) page： 339 - 346   2014

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.5194/npg-21-339-2014

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  45. Performance measurements of MHD simulation for planetary magnetosphere on Peta-scale computer FX10 Reviewed

    K. Fukazawa, T. Nanri, T. Umeda

    Parallel Computing: Accelerating Computational Science and Engineering, Advances in Parallel Computing   Vol. 25   page： 387 - 394   2014

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    DOI： 10.3233/978-1-61499-381-0-387

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  46. Performance evaluation of magnetohydrodynamics simulation for magnetosphere on K computer Reviewed

    K. Fukazawa, T. Nanri, T. Umeda

    AsiaSim 2013, Communications in Computer and Information Science   Vol. 402   page： 570-576   2013.11

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  47. Performance measurement of parallel Vlasov code for space plasma on scalar-type supercomputer systems with large number of cores Reviewed

    T. Umeda, K. Fukazawa

    AsiaSim 2013, Communications in Computer and Information Science   Vol. 402   page： 561-569   2013.11

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  48. A primitive kinetic-fluid model for quasi-parallel propagating magnetohydrodynamic waves

    Y. Nariyuki, S. Saito, T. Umeda

    Physics of Plasmas   Vol. 20 ( 7 )   2013.7

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    DOI： 10.1063/1.4816809

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  49. Global Vlasov simulation on magnetospheres of astronomical objects Reviewed

    Umeda Takayuki, Ito Yosuke, Fukazawa Keiichiro

    24TH IUPAP CONFERENCE ON COMPUTATIONAL PHYSICS (IUPAP-CCP 2012)   Vol. 454 ( 1 )   2013

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Journal of Physics: Conference Series  

    Space plasma is a collisionless, multi-scale, and highly nonlinear medium. There are various types of self-consistent computer simulations that treat space plasma according to various approximations. We develop numerical schemes for solving the Vlasov (collisionless Boltzmann) equation, which is the first-principle kinetic equation for collisionless plasma. The weak-scaling benchmark test shows that our parallel Vlasov code achieves a high performance and a high scalability. Currently, we use more than 1000 cores for parallel computations and apply the present parallel Vlasov code to various cross-scale processes in space plasma, such as a global simulation on the interaction between solar/stellar wind and magnetospheres of astronomical objects.

    DOI： 10.1088/1742-6596/454/1/012005

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  50. Performance measurement of magnetohydrodynamic code for space plasma on the typical scalar type supercomputer systems with the large number of cores Reviewed

    K. Fukazawa, T. Umeda

    International Journal of High Performance Computing   Vol. 26 ( 3 ) page： 310 - 318   2012.8

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    DOI： 10.1177/1094342011434813

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  51. A numerical electromagnetic linear dispersion relation for Maxwellian ring-beam velocity distributions Reviewed

    T. Umeda, S. Matsukiyo, T. Amano, Y. Miyoshi

    Physics of Plasmas   Vol. 19 ( 7 ) page： 072107   2012.7

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    DOI： 10.1063/1.4736848

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  52. Vlasov simulation of electrostatic solitary structures in multi-component plasmas Reviewed

    T. Umeda, M. Ashour-Abdalla, J. S. Pickett,M. L. Goldstein

    Journal of Geophysical Research   Vol. 117 ( 5 ) page： A05223   2012.5

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    DOI： 10.1029/2011JA017181

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  53. A scalable full electromagnetic Vlasov solver for cross-scale coupling in space plasma Reviewed

    T. Umeda, K. Fukazawa, Y. Nariyuki, T. Ogino

    IEEE Transactions on Plasma Science   Vol. 40 ( 5 ) page： 1421 - 1428   2012.5

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    DOI： 10.1109/TPS.2012.2188141

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  54. A non-oscillatory and conservative semi-Lagrangian scheme with fourth-degree polynomial interpolation for solving the Vlasov equation

    T. Umeda, Y. Nariyuki, D. Kariya

    Computer Physics Communications   Vol. 183 ( 5 ) page： 1094-1100   2012.5

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    DOI： 10.1016/j.cpc.2012.01.011

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  55. Microinstabilities at perpendicular collisionless shocks: A comparison of full particle simulations with different ion to electron mass ratio Reviewed

    T. Umeda, Y. Kidani, S. Matsukiyo, R. Yamazaki

    Physics of Plasmas   Vol. 19 ( 4 ) page： 042109   2012.4

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    DOI： 10.1063/1.3703319

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  56. Modified two-stream instability at perpendicular collisionless shocks: Full particle simulations Reviewed

    T. Umeda, Y. Kidani, S. Matsukiyo, R. Yamazaki

    Journal of Geophysical Research   Vol. 117 ( 3 ) page： A03206   2012.3

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    A full particle simulation study is carried out for studying microinstabilities generated in self-consistently excited perpendicular collisionless shocks. The present two-dimensional simulation with a high ion-to-electron mass ratio shows that the modified two-stream instability can be generated by the interaction of incoming and reflected ions with electromagnetic whistler mode waves propagating in the direction quasi-perpendicular to the ambient magnetic field. Properties of the excited whistler mode waves are consistent with the linear dispersion analysis based on the simulated velocity distribution functions. It is also found that the excited waves have an electron-scale wavelength in the shock-normal direction and an ion-scale wavelength in the shock-tangential direction, suggesting that the electron-scale microturbulences and the ion-scale shock structures are coupled with each other through the modified two-stream instability.

    DOI： 10.1029/2011JA017182

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  57. Effect of ion cyclotron motion on the structure of wakes: A Vlasov simulation Reviewed

    Umeda Takayuki

    EARTH PLANETS AND SPACE   Vol. 64 ( 2 ) page： 231 - 236   2012

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    The global structure of wake fields behind an unmagnetized object in the solar wind is studied by means of a 2.5-dimensional full electromagnetic Vlasov simulation. The interaction of a plasma flow with an unmagnetized object is quite different from that with a magnetized object such as the Earth. Due to the absence of the global magnetic field, the unmagnetized object absorbs plasma particles which reach the surface, generating a plasma cavity called a wake on the anti-solar side of the object. The interaction between the solar wind with an out-of-plane interplanetary magnetic field and an unmagnetized object of ion-gyro scale is examined to study the effect of the ion cyclotron motion on the structure of wake fields. It is shown that the wake boundary layer is broadened when the inner product of the electric force and the density gradient of the wake boundary layer is negative. On the other hand, a steep wake boundary layer is formed with a negative inner product. The result suggests that the structures of wake fields become asymmetric due to the in-plane E cross B drift motion of ions. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).

    DOI： 10.5047/eps.2011.05.035

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  58. Relativistic electron shock drift acceleration in low Mach number galaxy cluster shocks Reviewed

    S. Matsukiyo, Y. Ohira, R. Yamazaki, T. Umeda

    Astrophysical Journal   Vol. 742 ( 1 ) page： 47   2011.11

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  59. SUPPRESSION OF REFLECTED ELECTRONS BY KINETIC ALFVEN TURBULENCE IN A QUASI-PERPENDICULAR SHOCK: PARTICLE-IN-CELL SIMULATIONS Reviewed

    Saito S., Umeda T.

    ASTROPHYSICAL JOURNAL   Vol. 736 ( 1 )   2011.7

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    Shock drift acceleration is one of the important mechanisms for electron acceleration associated with magnetic mirror reflection along the magnetic field in a quasi-perpendicular collisionless shock. We study the influence of a rippled shock surface in the in-plane magnetic field on the magnetic mirror reflection of electrons. Simulation results show that the number of reflected electrons reduces after generation of the rippled shock surface. Electric and magnetic wavenumber spectra of the generated fluctuations in the shock transition region indicate the existence of kinetic Alfvén turbulence. The kinetic Alfvén turbulence decreases the electron pitch angle by parallel scattering, which reduces the magnetic mirror force acting on the electrons. These results suggest that the shock-generated kinetic Alfvén turbulence suppresses the magnetic mirror reflection of electrons during the shock drift acceleration. © 2011. The American Astronomical Society. All rights reserved.

    DOI： 10.1088/0004-637X/736/1/35

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  60. Nonlinear evolution of parallel propagating Alfven waves: Vlasov-MHD simulation Reviewed

    Y. Nariyuki, T. Umeda, T. Kumashiro, T. Hada

    Planetary and Space Science   Vol. 59 ( 8 ) page： 767-771   2011.6

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  61. Nonlinear evolution of parallel propagating Alfven waves: Vlasov-MHD simulation

    Y. Nariyuki, T. Umeda, T. Kumashiro, T. Hada

    Planetary and Space Science   Vol. 59 ( 8 ) page： 767-771   2011.6

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    DOI： 10.1016/j.pss.2011.02.017

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  62. Cross-scale coupling at a perpendicular collisionless shock

    T. Umeda, M. Yamao, R. Yamazaki

    Planetary and Space Science   Vol. 59 ( 7 ) page： 449-455   2011.5

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    DOI： 10.1016/j.pss.2010.01.007

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  63. Quasilinear theory and simulation of Buneman instability

    J. Pavan, P. H. Yoon, T. Umeda

    Physics of Plasmas   Vol. 18 ( 4 ) page： 42307   2011.4

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    DOI： 10.1063/1.3574359

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  64. Self-consistent kinetic numerical simulation model for ring current particles in the Earth's inner magnetosphere

    T. Amano, K. Seki, Y. Miyoshi, T. Umeda, Y. Matsumoto, Y. Ebihara, S. Saito

    Journal of Geophysical Research   Vol. 116 ( 2 ) page： 2216   2011.2

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    DOI： 10.1029/2010JA015682

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  65. Modeling nonlinear development of Buneman instability with linear dispersion theory Reviewed

    Jain Neeraj, Umeda Takayuki, Yoon Peter H.

    PLASMA PHYSICS AND CONTROLLED FUSION   Vol. 53 ( 2 )   2011.2

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    In this paper, spectra in the nonlinear phases of the Buneman instability are described by instantaneous linear dispersion theory. One-dimensional Vlasov simulation of the Buneman instability shows that nonlinear development is characterized by particle trapping in large-amplitude waves. Trapped particles form counter-streaming beam distribution function in velocity space. In addition to the low-frequency Buneman mode, the simulation also shows excitations of high-frequency electron plasma waves as well as wave modes propagating in the direction opposite to the original electron beam. The actual physics of the wave dynamics is very complicated to analyze. However, by employing linear dispersion theory on the basis of instantaneous electron distributions it is possible to relate the generation of waves to the particle distribution. Specifically, it is shown that excitations of various waves are intimately related to the counter-streaming electron beam distribution. The present approach can be a useful diagnostic tool based upon which an intuitive understanding of the complicated nonlinear physics can be attained. © 2011 IOP Publishing Ltd Printed in the UK & the USA.

    DOI： 10.1088/0741-3335/53/2/025010

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  66. Vlasov simulation on the interaction between solar wind and a dielectric body

    T. Umeda, T. Kimura, K. Togano, K. Fukazawa, Y. Matsumoto, T. Miyoshi, N. Terada, T. K. M. Nakamura, T. Ogino

    Physics of Plasmas   Vol. 18 ( 1 ) page： 12908   2011.1

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    DOI： 10.1063/1.3551510

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  67. Vlasov Code Simulation of Cross-scale Coupling in Space Plasmas

    Umeda Takayuki, Matsumoto Yosuke, Nakamura Takuma K. M., Fukazawa Keiichiro, Ogino Tatsuki

    NUMERICAL MODELING OF SPACE PLASMA FLOWS - ASTRONUM 2010   Vol. 444   page： 182-+   2011

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  68. Nonlinear turbulence theory and simulation of Buneman instability

    P. H. Yoon, T. Umeda

    Physics of Plasmas   Vol. 17 ( 11 ) page： 112317   2010.11

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    DOI： 10.1063/1.3517103

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  69. On the reformation at quasi- and exactly-perpendicular shocks: Full particle-in-cell simulations

    T. Umeda, Y. Kidani, M. Yamao, S. Matsukiyo, R. Yamazaki

    Journal of Geophysical Research   Vol. 115 ( 10 ) page： 10250   2010.10

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    DOI： 10.1029/2010JA015458

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  70. Comparative study of global MHD simulations of the terrestrial magnetosphere with different numerical schemes

    Y. Matsumoto, N. Terada, T. Miyoshi, K. Fukazawa, T. Umeda, T. Ogino, K. Seki

    IEEE Transactions on Plasma Science   Vol. 38 ( 9 ) page： 2229-2235   2010.9

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    DOI： 10.1109/TPS.2010.2056704

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  71. Performance measurement of magneto-hydro-dynamic code for space plasma on the various scalar type supercomputer systems

    K. Fukazawa, T. Umeda, T. Miyoshi, N. Terada, Y. Matsumoto, T. Ogino

    IEEE Transactions on Plasma Science   Vol. 38 ( 9 ) page： 2254-2259   2010.9

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    DOI： 10.1109/TPS.2010.2055162

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  72. The HLLD approximate Riemann solver for magnetospheric simulation

    T. Miyoshi, N. Terada, Y. Matsumoto, K. Fukazawa, T. Umeda, K. Kusano

    IEEE Transactions on Plasma Science   Vol. 38 ( 9 ) page： 2236-2242   2010.9

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    DOI： 10.1109/TPS.2010.2057451

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  73. Full electromagnetic Vlasov code simulation of the Kelvin-Helmholtz instability

    T. Umeda, J. Miwa, Y. Matsumoto, T. K. M. Nakamura, K. Togano, K. Fukazawa, I. Shinohara

    Physics of Plasmas   Vol. 17 ( 5 ) page： 52311   2010.5

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    DOI： 10.1063/1.3422547

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  74. On the nonlinearity of the Langmuir turbulence excited by a weak electron beam-plasma interaction

    Y. Nariyuki, T. Umeda

    Physics of Plasmas   Vol. 17 ( 5 ) page： 54506   2010.5

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    DOI： 10.1063/1.3425872

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  75. Structures of diffusion regions in collisionless magnetic reconnection

    T. Umeda, K. Togano, T. Ogino

    Physics of Plasmas   Vol. 17 ( 5 ) page： 52103   2010.5

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    DOI： 10.1063/1.3403345

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  76. Electromagnetic plasma emission during beam-plasma interaction: Parametric decay versus induced scattering

    T. Umeda

    Journal of Geophysical Research   Vol. 115 ( 1 ) page： 1204   2010.1

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    DOI： 10.1029/2009JA014643

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  77. Vlasov simulation of finite amplitude magnetohydrodynamic waves in the solar wind: Development of Vlasov-Hall-MHD code

    T. Kumashiro, T. Hada, Y. Nariyuki, T. Umeda

    Journal of Plasma and Fusion Research SERIES   Vol. 8   page： 831-836   2009.9

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  78. Implementation of non-oscillatory and conservative scheme into magnetohydrodynamic equations

    S. Tanaka, T. Umeda, Y. Matsumoto, T. Miyoshi, T. Ogino

    Earth, Planets and Space   Vol. 61 ( 7 ) page： 895-903   2009.7

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  79. Cluster observations and numerical modeling of energy-dispersed Ionospheric H+ ions bouncing at the PSBL

    J. M. Bosqued, M. Ashour-Abdalla, T. Umeda, M. El Alaoui, V. Peroomian, H. U. Frey, A. Marchaudon, H. Laakso

    Journal of Geophysical Research   Vol. 114 ( 4 )   2009.4

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    DOI： 10.1029/2008JA013562

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  80. Electron acceleration at a low-Mach-number perpendicular collisionless shock Reviewed

    T. Umeda, M. Yamao, R. Yamazaki

    Astrophysical Journal   Vol. 695 ( 1 ) page： 574-579   2009.4

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    A full particle simulation study is carried out on the electron acceleration at a collisionless, relatively low Alfven Mach number (M_A = 5), perpendicular shock. Recent self-consistent hybrid shock simulations have demonstrated that the shock front of perpendicular shocks has a dynamic rippled character along the shock surface of low Mach number perpendicular shocks. In this paper, the effect of the rippling of perpendicular shocks on the electron acceleration is examined by means of large-scale (ion-scale) two-dimensional full particle simulations. It has been shown that a large-amplitude electric field is excited at the shock front in association with the ion-scale rippling, and that reflected ions are accelerated upstream at a localized region where the shock-normal electric field of the rippled structure is polarized upstream. The current-driven instability caused by the highly accelerated reflected ions has a high growth rate of up to large-amplitude electrostatic waves. Energetic electrons are then generated by the large-amplitude electrostatic waves via electron surfing acceleration at the leading edge of the shock-transition region. The present result suggests that the electron surfing acceleration is also a common feature at low Mach number perpendicular collisionless shocks.

  81. Two-dimensional full-electromagnetic Vlasov code with conservative scheme and its application to magnetic reconnection

    T. Umeda, K. Togano, T. Ogino

    Computer Physics Communications   Vol. 180 ( 3 ) page： 365-374   2009.3

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    A detailed procedure of full-electromagnetic Vlasov simulation technique is presented. Our new unsplitting conservative scheme exactly satisfies the continuity equation for charge. The implicit Finite Difference Time Domain method is also adopted for computation of electromagnetic fields, which is not restricted by the CFL condition for light. The Geospace Environment Modeling magnetic reconnection challenge problem is adopted as a benchmark test. The characteristics of the present Vlasov code are studied by varying the resolution in configuration space.

    DOI： 10.1016/j.cpc.2008.11.001

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  82. Implementation of a non-oscillatory and conservative scheme into magnetohydrodynamic equations Reviewed

    Tanaka Shin, Umeda Takayuki, Matsumoto Yosuke, Miyoshi Takahiro, Ogino Tatsuki

    EARTH PLANETS AND SPACE   Vol. 61 ( 7 ) page： 895 - 903   2009

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    We present a magnetohydrodynamic (MHD) simulation technique with a new non-oscillatory and conservative interpolation scheme. Several high-resolution and stable numerical schemes have recently been proposed for solving the MHD equations. To apply the CIP scheme to the hydrodynamic equations, we need to add a certain diffusion term to suppress numerical oscillations at discontinuities. Although the TVD schemes can automatically avoid numerical oscillations, they are not appropriate for profiles with a local maximum or minimum, such as waves. To deal with the above problems, we implement a new non-oscillatory and conservative interpolation scheme in MHD simulations. Several numerical tests are carried out in order to compare our scheme with other recent high-resolution schemes. The numerical tests suggest that the present scheme can follow long-term evolution of both Alfvén waves and compressive shocks. The present scheme has been used for a numerical modeling of Alfvén waves in the solar wind, in which sinusoidal Alfvén waves decay into compressive sound waves that steepen into shocks.rigaku corporation, japan. Copyright © the society of geomagnetism and earth.

    DOI： 10.1186/BF03353200

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  83. Vlasov simulation of Langmuir decay instability

    T. Umeda, T. Ito

    Physics of Plasmas   Vol. 15 ( 8 ) page： 84503   2008.8

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    DOI： 10.1063/1.2965494

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  84. Two-dimensional full particle simulation of a perpendicular collisionless shock with a shock-rest-frame model

    Umeda Takayuki, Yamao Masahiro, Yamazaki Ryo

    ASTROPHYSICAL JOURNAL LETTERS   Vol. 681 ( 2 ) page： L85-L88   2008.7

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    Web of Science

  85. Generation of low-frequency electrostatic and electromagnetic waves as nonlinear consequences of beam-plasma interactions Reviewed

    Umeda Takayuki

    PHYSICS OF PLASMAS   Vol. 15 ( 6 )   2008.6

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Physics of Plasmas  

    Nonlinear evolution of the electron two-stream instability in a current-carrying plasma is examined by using a two-dimensional electromagnetic particle-in-cell simulation. Formation of electron phase-space holes is observed as an early nonlinear consequence of electron-beam-plasma interactions. Lower-hybrid waves, electrostatic, and electromagnetic whistler mode waves are also excited by different mechanisms during the ensuing nonlinear wave-particle interactions. It is shown by the present computer simulation with a large simulation domain and a long simulation time that these low-frequency waves can disturb the electrostatic equilibrium of electron phase-space holes, suggesting that the lifetime of electron phase-space holes sometimes becomes shorter in a current-carrying plasma. © 2008 American Institute of Physics.

    DOI： 10.1063/1.2937818

    Web of Science

    Scopus

  86. Modeling PSBL high speed ion beams observed by Cluster and Double Star

    M. Ashour-Abdalla, J. M. Bosqued, M. El Alaoui, V. Peroomian, T. Umeda, J. Walker

    Advances in Space Research   Vol. 41 ( 10 ) page： 1598-1610   2008

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1016/j.asr.2007.04.018

    Web of Science

    Scopus

    J-GLOBAL

  87. A conservative and non-oscillatory scheme for Vlasov code simulations Reviewed

    Umeda Takayuki

    EARTH PLANETS AND SPACE   Vol. 60 ( 7 ) page： 773 - 779   2008

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    Language：Japanese   Publishing type：Research paper (scientific journal)  

    Web of Science

  88. Parametric decay of Alfven waves

    S. Tanaka, T. Ogino, T. Umeda

    Journal of Geophysical Research   Vol. 112 ( A10 ) page： 10110   2007.10

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1029/2007JA012513

    Web of Science

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  89. Turbulent acceleration of superthermal electrons,

    C.-M. Ryu, T. Rhee, T. Umeda, P. H. Yoon, and Y. Omura

    Physics of Plasmas   Vol. 14 ( 10 ) page： 100701   2007.10

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1063/1.2779282

    Web of Science

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    J-GLOBAL

  90. Particle-in-cell simulation of Maxwellian ring velocity distribution

    T. Umeda, M. Ashour-Abdalla, D. Schriver, R. L. Richard, F. V. Coroniti

    Journal of Geophysical Research   Vol. 112 ( A4 ) page： 4212   2007.4

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1029/2006JA012124

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  91. Vlasov simulation of Langmuir wave packets

    Umeda T.

    Nonlinear Processes in Geophysics   Vol. 14 ( 5 ) page： 671-679   2007.1

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.5194/npg-14-671-2007

    Scopus

  92. Numerical study of electrostatic electron cyclotron harmonic waves due to Maxwellian ring velocity distributions

    Umeda Takayuki

    EARTH PLANETS AND SPACE   Vol. 59 ( 11 ) page： 1205-1210   2007

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    Language：English   Publishing type：Research paper (scientific journal)  

    Web of Science

  93. Comparison of numerical interpolation schemes for one-dimensional electrostatic Vlasov code

    T. Umeda, M. Ashour-Abdalla, D. Schriver

    Journal of Plasma Physics   Vol. 72 ( 6 ) page： 1057-1060   2006.12

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1017/S0022377806005228

    Web of Science

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    J-GLOBAL

  94. Nonlinear evolution of the electron two-stream instability: Two-dimensional particle simulations

    T. Umeda, Y. Omura, T. Miyake, H. Matsumoto, M. Ashour-Abdalla

    Journal of Geophysical Research   Vol. 111 ( A10 ) page： 10206-10206   2006.10

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1029/2006JA011762

    Web of Science

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    J-GLOBAL

  95. Vlasov simulation of amplitude-modulated Langmuir waves Reviewed

    Umeda Takayuki

    PHYSICS OF PLASMAS   Vol. 13 ( 9 )   2006.9

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    Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Physics of Plasmas  

    Mechanisms for the generation of Langmuir wave packets are studied by performing a one-dimensional electrostatic Vlasov simulation. The present simulation of a weak-electron-beam instability without ion dynamics suggests two new processes for the amplitude modulation of Langmuir waves. The beam instability excites Langmuir modes over a wide wave number range, but the saturation of the most unstable Langmuir mode "filters" the growth of sideband modes. Specific upper and lower sideband modes linearly grow to a high saturation level. Then the primary Langmuir mode is amplified and strongly modulated through interaction with the sideband modes. © 2006 American Institute of Physics.

    DOI： 10.1063/1.2348088

    Web of Science

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  96. Cluster observations of energetic ionospheric ion beams in the auroral region: Acceleration and associated energy-dispersed precipitation

    J. M. Bosqued, M. Ashour-Abdalla, A. Marchaudon, H. Laakso, T. Umeda, M. El Alaoui, V. Peroomian, H. Reme, G. Paschmann, M. Dunlop, A. Fazakerley

    Geophysical Research Letters   Vol. 33 ( 12 ) page： 12102-12102   2006.6

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1029/2006GL025708

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    J-GLOBAL

  97. Full particle simulation of a perpendicular collisionless shock: A shock-rest-frame model Reviewed

    Umeda Takayuki, Yamazaki Ryo

    EARTH PLANETS AND SPACE   Vol. 58 ( 12 ) page： E41 - E44   2006

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：Earth, Planets and Space  

    The full kinetic dynamics of a perpendicular collisionless shock is studied by means of a one-dimensional electromagnetic full particle simulation. The present simulation domain is taken in the shock rest frame in contrast to the previous full particle simulations of shocks. Preliminary results show that the downstream state falls into a unique cyclic reformation state for a given set of upstream parameters through the self-consistent kinetic processes. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.

    DOI： 10.1186/BF03352617

    Web of Science

    Scopus

  98. Two-dimensional particle simulation of electromagnetic field signature associated with electrostatic solitary waves Reviewed

    T. Umeda, Y. Omura, H. Matsumoto

    Journal of Geophysical Research   Vol. 109 ( A2 ) page： A02207   2004.2

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

  99. A new charge conservation method in electromagnetic particle-in-cell simulations Reviewed

    T. Umeda, Y. Omura, T. Tominaga, H. Matsumoto

    Computer Physics Communication   Vol. 156 ( 1 ) page： 73-85   2003.12

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

  100. Particle simulation of plasma response to an applied electric field parallel to magnetic field lines Reviewed

    Y. Omura, W. J. Heikkila, T. Umeda, K. Ninomiya, H. Matsumoto

    Journal of Geophysical Research   Vol. 108 ( A5 ) page： 1197   2003.5

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  101. Harmonic Langmuir waves. III. Vlasov simulation Reviewed

    T. Umeda, Y. Omura, P. H. Yoon, R. Gaelzer, H. Matsumoto

    Physics of Plasmas   Vol. 10 ( 2 ) page： 382-391   2003.2

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

  102. Harmonic Langmuir waves. I. Nonlinear dispersion relation Reviewed

    P. H. Yoon, R. Gaelzer, T. Umeda, Y. Omura, H. Matsumoto

    Physics of Plasmas   Vol. 10 ( 2 ) page： 364-372   2003.2

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  103. Harmonic Langmuir waves. II. Turbulence spectrum Reviewed

    R. Gaelzer, P. H. Yoon, T. Umeda, Y. Omura, H. Matsumoto

    Physics of Plasmas   Vol. 10 ( 2 ) page： 373-381   2003.2

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    Language：English   Publishing type：Research paper (scientific journal)  

  104. Formation of electrostatic solitary waves in space plasmas: Particle simulations with open boundary conditions Reviewed

    T. Umeda, Y. Omura, H. Matsumoto, H. Usui

    Journal of Geophysical Research   Vol. 107 ( A12 ) page： 1449   2002.12

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

  105. An improved masking method for absorbing boundaries in electromagnetic particle simulations Reviewed

    T. Umeda, Y. Omura, H. Matsumoto

    Computer Physics Communication   Vol. 137 ( 2 ) page： 286-299   2001.6

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    Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

  106. Observational evidence of dissipative small scale processes: Geotail spacecraft observation and simulation of electrostatic solitary waves Reviewed

    Y. Omura, H. Kojima, T. Umeda, H. Matsumoto

    Astrophysics and Space Science   Vol. 277 ( 1 ) page： 45-57   2001.4

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Books 3

  1. Simulation of collisionless plasma with the vlasov method

    Umeda T.（ Role： Sole author）

    Computer Physics  2012.12  （ ISBN:9781613247907 ）

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    Language：Japanese

    Numerical schemes for solving the Vlasov-Maxwell system of equations are presented. Our Universe is filled with collisionless plasma, which is a dielectric medium with nonlinear interactions between charged particles and electromagnetic fields. Thus computer simulations play an essential role in studies of such highly nonlinear systems. The full kinetics of collisionless plasma is described by the Vlasov-Maxwell equations. Since the Vlasov equation treats charged particles as position-velocity phase-space distribution functions in hyper dimensions, huge supercomputers and highly-scalable parallel codes are essential. Recently, a new parallel Vlasov-Maxwell solver is developed by adopting a stable but less-dissipative scheme for time integration of conservation laws, which has successfully achieved a high scalability on massively parallel supercomputers with multi-core scalar processors. The new code has applied to 2P3V (two dimensions for position and three dimensions for velocity) problems of cross-scale plasma processes such as magnetic reconnection, Kelvin-Helmholtz instability and the interaction between the solar wind and an asteroid. © 2012 Nova Science Publishers, Inc. All rights reserved.

    Scopus

  2. Electromagnetic waves in plasma

    T. Umeda（ Role： Sole author）

    In Tech  2011.3  （ ISBN:978-953-307-275-3 ）

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    Language：Japanese

  3. Simulation of electron beam instabilities and nonlinear potential structures

    Y. Omura, T. Umeda, and H. Matsumoto（ Role： Joint author）

    Springer-Verlag Berlin Heidelberg  2003.6  （ ISBN:978-354-000-698-2 ）

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    Language：English

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Presentations 39

  1. Paradigm shift in program structure of particle-in-cell simulations

    Umeda T.

    Advances in Parallel Computing 

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    Event date： 2020

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.3233/APC200072

    Scopus

  2. Performance Comparison of Eulerian Kinetic Vlasov Code Between Xeon Phi KNL and Xeon Broadwell

    Umeda T.

    Communications in Computer and Information Science 

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    Event date： 2018

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.1007/978-981-13-2853-4_12

    Scopus

  3. Hybrid parallelization of hyper-dimensional Vlasov code with OpenMP loop collapse directive

    Umeda T.

    Advances in Parallel Computing 

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    Event date： 2016.1

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.3233/978-1-61499-621-7-265

    Scopus

  4. Performance measurements of MHD simulation for planetary magnetosphere on Peta-scale computer FX10

    K. Fukazawa, T. Nanri, T. Umeda

    Parallel Computing: Accelerating Computational Science and Engineering, Advances in Parallel Computing 

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    Event date： 2014.1

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.3233/978-1-61499-381-0-387

    Scopus

  5. Performance evaluation of magnetohydrodynamics simulation for magnetosphere on K computer

    K. Fukazawa, T. Nanri, T. Umeda

    AsiaSim 2013, Communications in Computer and Information Science 

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    Event date： 2013.1

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.1007/978-3-642-45037-2_61

    Scopus

  6. Performance measurement of parallel Vlasov code for space plasma on scalar-type supercomputer systems with large number of cores

    T. Umeda, K. Fukazawa

    AsiaSim 2013, Communications in Computer and Information Science 

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    Event date： 2013.1

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.1007/978-3-642-45037-2_60

    Scopus

  7. Performance measurement of parallel Vlasov code for space plasma on various scalar-type supercomputer systems

    Umeda T.

    Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 

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    Event date： 2012.10

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.1007/978-3-642-33078-0_17

    Scopus

  8. On the reformation at perpendicular shocks

    T. Umeda, Y. Kidani, S. Matsukiyo

    American Geophysical Union 2011 Fall meeting 

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    Event date： 2011.12

    Language：English   Presentation type：Oral presentation (general)  

  9. Dynamics of quasi-perpendicular shocks: Recent results issued from 2D PIC simulation

    Umeda T.

    2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011 

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    Event date： 2011.11

    Language：English   Presentation type：Oral presentation (general)  

    DOI： 10.1109/URSIGASS.2011.6051058

    Scopus

  10. Study of the moon-solar wind interaction with parallel kinetic plasma simulations

    T. Umeda, Y. Ito, Y. Kidani, K. Fukazawa

    International Conference for High Performance Computing, Networking, Storage and Analysis 2011 

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    Event date： 2011.11

    Language：English   Presentation type：Oral presentation (general)  

  11. Dynamics of quasi-perpendicular shocks: Recent results issued from 2D PIC simulation

    T. Umeda, Y. Kidani, S. Matsukiyo

    30th General Assembly of the International Union of Radio Science (URSI) 

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    Event date： 2011.8

    Language：English   Presentation type：Oral presentation (general)  

  12. Recent Advancement in Vlasov code simulations

    T. Umeda

    10th International School for Space Simulations (ISSS-10) 

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    Event date： 2011.7

    Language：English   Presentation type：Oral presentation (general)  

  13. Highly scalable full electromagnetic Vlasov solver for cross-scale coupling in space plasma

    T. Umeda, K. Fukazawa, Y. Nariyuki, Y. Matsumoto, T. K. M. Nakamura

    International Conference for High Performance Computing, Networking, Storage and Analysis 2010 

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    Event date： 2010.11

    Language：English   Presentation type：Oral presentation (general)  

  14. Effect of ion cyclotron motion on the structure of wakes International conference

    5th Alfven Conference on Plasma Interaction with Non-magnetized Planets/Moons and its Influence on Planetary Evolution 

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    Event date： 2010.10

    Language：Japanese   Presentation type：Oral presentation (general)  

    Country：Japan  

  15. Electromagnetic plasma emission during beam-plasma interaction International conference

    2010 Asia-Pacific Radio Science Conference 

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    Event date： 2010.9

    Language：English   Presentation type：Oral presentation (invited, special)  

    Country：Japan  

  16. Cross-scale coupling at a collisionless shock

    38th COSPAR Scientific Assembly 

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    Event date： 2010.7

    Language：English   Presentation type：Oral presentation (general)  

  17. Vlasov code simulation of cross-scale coupling in space plasmas International conference

    5th International Conference on Numerical Modeling of Space Plasma Flows 

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    Event date： 2010.6

    Language：English   Presentation type：Oral presentation (general)  

  18. STPシミュレーションの過去・現在・未来

    梅田 隆行

    宇宙地球惑星科学若手会 2009年夏の学校 

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    Event date： 2009.9

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

    Country：Japan  

  19. Cross-scale coupling at a collisionless shock International conference

    International Association of Geomagnetism and Aeronomy (IAGA) 11th Scientific Assembly 

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    Event date： 2009.8

    Language：English   Presentation type：Oral presentation (general)  

  20. New Vlasov simulation techniques for multi-scale dynamics of magnetosphere International conference

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    Event date： 2009.8

    Language：English   Presentation type：Oral presentation (invited, special)  

  21. Simulations and numerical linear analyses of kinetic instabilities International conference

    9th International School for Space Simulations 

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    Event date： 2009.7

    Language：English   Presentation type：Oral presentation (invited, special)  

  22. ブラソフシミュレーションでジオスペースを解く

    梅田 隆行

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    Event date： 2009.3

    Language：Japanese   Presentation type：Oral presentation (general)  

    Country：Japan  

  23. New Vlasov simulation techniques for scale coupling in the plasma universe International conference

    Workshop on Cross-Scale Coupling in Plasmas 

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    Event date： 2009.3

    Language：English   Presentation type：Oral presentation (general)  

  24. Status of Japanese young simulationists International conference

    ERG, SCOPE and Beyond 

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    Event date： 2008.11

    Language：English   Presentation type：Oral presentation (invited, special)  

    Country：Japan  

  25. STPシミュレーションコード開発の将来展望

    梅田 隆行, 寺田 直樹, 杉山 徹, 三好 隆博, 松本 洋介, 加藤 雄人, 深沢 圭一郎, 篠原 育, 中村琢磨

    第124回地球電磁気・地球惑星圏学会 

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    Event date： 2008.10

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

    Country：Japan  

  26. Two-dimensional Vlasov code simulation of magnetic reconnection International conference

    US-Japan Workshop on Magnetic Reconnection 2008 

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    Event date： 2008.3

    Language：English   Presentation type：Oral presentation (general)  

    Country：Japan  

  27. ブラソフシミュレーションで拓く太陽地球惑星科学

    梅田 隆行, 寺田 直樹, 杉山 徹, 三好 隆博, 松本 洋介, 加藤 雄人, 深沢 圭一郎, 篠原 育

    第21回数値流体力学シンポジウム 

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    Event date： 2007.12

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

    Country：Japan  

  28. Full particle simulation of perpendicular collisionless shocks with a shock-rest-frame model International conference

    American Geophysical Union 2007 Fall meeting 

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    Event date： 2007.12

    Language：English   Presentation type：Oral presentation (general)  

  29. Vlasov simulation of beam-plasma interactions International conference

    8th International School/Symposium for Space Simulations 

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    Event date： 2007.2

    Language：English   Presentation type：Oral presentation (invited, special)  

  30. Polynomial interpolation for hyperbolic conservation laws (PIC) scheme: Application to Vlasov Simulations International conference

    CAWSES International Workshop on Space Weather Modeling 

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    Event date： 2006.11

    Language：English   Presentation type：Oral presentation (general)  

    Country：Japan  

  31. Vlasov simulation of amplitude-modulated Langmuir waves International conference

    6th International Workshop on Nonlinear Waves and Turbulence in Space Plasmas 

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    Event date： 2006.10

    Language：English   Presentation type：Oral presentation (invited, special)  

    Country：Japan  

  32. Nonlinear evolution of electron two-stream instability: Two-dimensional particle simulation International conference

    28th General Assembly of the International Union of Radio Science 

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    Event date： 2005.10

    Language：English   Presentation type：Oral presentation (general)  

  33. Generation of electron cyclotron harmonic (ECH) waves due to loss cone distribution functions International conference

    American Geophysical Union 2004 Fall meeting 

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    Event date： 2004.12

    Language：English   Presentation type：Oral presentation (general)  

  34. Particle simulations of electrostatic solitary waves in space plasmas International conference

    7th International Workshop on the Interrelationship between Plasma Experiments in Laboratory and Space 

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    Event date： 2004.7

    Language：English   Presentation type：Oral presentation (invited, special)  

  35. Particle simulations of electromagnetic emissions from electrostatic solitary waves International conference

    23rd General Assembly of the International Union of Geodesy and Geophysics 

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    Event date： 2003.7

    Language：English   Presentation type：Oral presentation (general)  

    Country：Japan  

  36. Particle simulations of electromagnetic emissions from electrostatic solitary waves International conference

    27th General Assembly of the International Union of Radio Science 

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    Event date： 2002.8

    Language：English   Presentation type：Oral presentation (general)  

  37. Formation of electrostatic solitary waves: Two-dimensional particle simulation with open boundary conditions International conference

    2002 Western Pacific Geophysics Meeting 

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    Event date： 2002.7

    Language：English   Presentation type：Oral presentation (general)  

  38. An improved masking method for absorbing boundaries in electromagnetic particle simulations International conference

    6th International School/Symposium for Space Simulations 

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    Event date： 2001.9

    Language：English   Presentation type：Oral presentation (invited, special)  

  39. Electromagnetic particle simulation of electron beam instabilities in 2-D open system International conference

    2001 Asia-Pacific Radio Science Conference 

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    Event date： 2001.8

    Language：English   Presentation type：Oral presentation (general)  

    Country：Japan  

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KAKENHI (Grants-in-Aid for Scientific Research) 8

  1. How do fluid simulations reproduce kinetic simulation results?

    Grant number：19H01868  2019.4 - 2024.3

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    Authorship：Principal investigator 

    Grant amount：\16510000 （ Direct Cost: \12700000 、 Indirect Cost：\3810000 ）

  2. Study of unified numerical schemes for numerical simulations of electromagnetic fluid plasma: From MHD to multi fluids

    Grant number：15K13572  2015.4 - 2018.3

    UMEDA TAKAYUKI

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    Authorship：Principal investigator 

    Grant amount：\3510000 （ Direct Cost: \2700000 、 Indirect Cost：\810000 ）

    The nonlinear evolution of the Kelvin-Helmholtz instability (KHI) and the Rayleigh-Taylor instability (RTI) at a density shear layer transverse to magnetic field in collisionless plasma is investigated by means of a fully kinetic Vlasov simulation with two spatial and two velocity dimensions. Several simulation runs with different ratio of the ion inertial length and/or ion gyro radius to the thickness of the initial shear layer have been performed to discuss “non-MHD effects” such as the ion inertial (Hall) effect and the ion finite Larmor radius (FLR) effect. The result shows that the instabilities develop symmetrically when neither Hall effect or FLR effect are available. An asymmetric development of the instabilities is seen when the Hall effect is available. When the FLR effect is available, a different type of instability with a spatial scale of ion gyro radius is generated, which disturbs the development of the primary instabilities.

  3. Generation of cosmic-ray protons at collisionless shocks via hybrid particle-in-cell simulations

    Grant number：26287041  2014.4 - 2018.3

    UMEDA TAKAYUKI

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    Authorship：Principal investigator 

    Grant amount：\15470000 （ Direct Cost: \11900000 、 Indirect Cost：\3570000 ）

    The computational speed of the particle-in-cell-type plasma simulation codes is accelerated by using the counting sort algorithm and the array-particle data structure. Large-scale two-dimensional particle-in-cell simulations are carried out by using the improved code for studying non-stationarity of perpendicular shocks called the reformation. The result implies that the existence of the reformation is controlled by types of micro-instabilities at the shock transition layer.
    One- and two-dimensional particle simulations are also carried out on the development of a large-amplitude whistler-mode waves in the shock transition layer. Relativistic electron acceleration is found in the 1D run. On the other hand, a rapid decay of whistler-mode waves through a new instability is found in the 2D run, which suppress the relativistic electron acceleration.

  4. Six-dimensional plasma simulation

    Grant number：25610144  2013.4 - 2015.3

    UMEDA Takayuki

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    Authorship：Principal investigator 

    Grant amount：\3250000 （ Direct Cost: \2500000 、 Indirect Cost：\750000 ）

    A fully six-dimensional electromagnetic Vlasov code has been developed. Work arrays and memory space for the computation of the advection in the configuration space are substantially saved by the transposition of the data arrays for distribution functions. It is confirmed that the transposition efficiently accelerates the computational speed on x86 CPUs. While on SPARC CPUs, the computational efficiency becomes slightly worse.
    We also performed large-scale Vlasov simulation of the Kelvin-Helmholtz instability (KHI) and a weakly-magnetized small body. It is shown that ion-scale secondary instabilities taking place during the nonlinear development of MHD-scale primary KHI are affected by the structure of secondary velocity-shear layers of primary KH vortices. On the other hand, electron-scale charge separation does not affect the structure of MHD-scale magnetosphere but affects wave activities inside the magnetosphere.

  5. Study of cross-scale coupling in space plasma via large-scale Vlasov simulations

    Grant number：23740367  2011 - 2012

    UMEDA Takayuki

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    Authorship：Principal investigator 

    Grant amount：\3900000 （ Direct Cost: \3000000 、 Indirect Cost：\900000 ）

    We study numerical schemes for the first-principle Vlasov code as a post-Peta-scale computer simulation technique of space plasma. We developed numerical algorithms for solving the collisionless Boltzmann (Vlasov) equation which is a hyper-dimensional conservation law. The new simulation code is parallelized for scalar massively parallel computers with more than 10,000 CPU cores. The new code is applied to various multi-scale processes in space plasma. The first global Vlasov simulation of a magnetized astronomical body is succeeded. Also, it is shown that temporal evolution of fluid-scale Kelvin-Helmholtz vortices generated at a velocity-shear layer is strongly affected by the particle-scale ion gyro motion.

  6. Study of particle acceleration processes at collisionless shocks via next-generation and first-principle particle simulations

    Grant number：21200050  2009 - 2011

    Grant-in-Aid for Scientific Research on Innovative Areas (Research a proposed research project)

    UMEDA Takayuki

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    Authorship：Principal investigator 

    Grant amount：\27040000 （ Direct Cost: \20800000 、 Indirect Cost：\6240000 ）

    Large-scale two-dimensional full particle-in-cell simulations are carried out for studying non-stationarity of perpendicular shocks. It is confirmed that the persistence and absence of the self-reformation is controlled by micro-instabilities at the shock front. When electromagnetic whistler mode waves are strongly excited by the modified two-stream instability, both incoming and reflected ions are strongly scattered and the shock reformation becomes absent. On the other hand, when electrostatic waves are weakly excited or there is no micro-instabilities, reflected ions show a coherent behavior and the shock reformation is persistent. In this case, however, the reformation period is modified essentially due to the shock front ripples. The present simulation result suggests that the structure and dynamics of shocks are affected by the cross-scale coupling between electron-scale micro-instabilities and ion-scale shock-front ripples.

  7. Study of Vlasov simulation techniques for next-generation supercomputers

    Grant number：21740352  2009 - 2010

    UMEDA Takayuki

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    Authorship：Principal investigator 

    Grant amount：\3510000 （ Direct Cost: \2700000 、 Indirect Cost：\810000 ）

    We study numerical schemes for the first-principle Vlasov code as a second-next-generation computer simulation technique of space plasma. We developed numerical algorithms for solving the collisionless Boltzmann (Vlasov) equation which is a hyper-dimensional conservation law. The new simulation code is parallelized for scalar massively parallel computers and has achieved more than 80% parallel efficiency on more than 1,000 CPU cores. The new code is applied to various multi-scale processes in space plasma. The numerical results imply the existence of cross-scale coupling between fluid scale and particle scale.

  8. Study of Revolutionary Vlasov simulation techniques

    Grant number：19840024  2007 - 2008

    Grant-in-Aid for Young Scientists (Start-up)

    UMEDA Takayuki

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    Authorship：Principal investigator 

    Grant amount：\3105000 （ Direct Cost: \2700000 、 Indirect Cost：\405000 ）

▼display all

To the head of KAKENHI (Grants-in-Aid for Scientific Research).▲

Industrial property rights 1

  1. 相対論的運動方程式に基づく荷電粒子の運動解析方法

    梅田隆行

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    Application no：2022-032260  Date applied：2022.3

To the head of Industrial property rights.▲
 

Teaching Experience (On-campus) 32

  1. Electric Circuits with Exercises

    2020

  2. Data processing and analysis excerise

    2020

  3. Data processing and analysis excerise

    2019

  4. 電気回路論演習

    2019

  5. Space information engineering

    2019

  6. 企業・研究所見学Ｂ

    2019

  7. 実世界データ処理学

    2019

  8. Data processing and analysis excerise

    2018

  9. 電気回路論演習

    2018

  10. 電気回路論演習

    2017

  11. Data processing and analysis excerise

    2017

  12. 電気回路論演習

    2016

  13. データ解析処理論演習

    2016

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  14. 電気回路論演習

    2015

  15. データ解析処理論演習

    2015

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  16. 電気回路論演習

    2014

  17. データ解析処理論演習

    2014

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  18. 電気回路論演習

    2013

  19. データ解析処理論演習

    2013

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  20. 電気回路論演習

    2012

  21. データ解析処理論演習

    2012

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  22. データ解析処理論演習

    2011

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  23. 電気回路論演習

    2011

  24. データ解析処理論演習

    2010

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  25. 電子情報回路工学演習

    2010

  26. 電子情報回路工学演習

    2009

  27. データ解析処理論演習

    2009

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  28. 電子情報回路工学演習

    2008

  29. データ解析処理論演習

    2008

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  30. データ解析処理論演習

    2007

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

  31. 電子情報回路工学演習

    2007

  32. データ解析処理論演習

    2006

    　詳細を見る

    数値解析ソフトScilabの使用法を習得し、人工衛星が観測したデータを解析する

▼display all

To the head of Teaching Experience (On-campus).▲
 

Social Contribution 3

  1. 平成27年度「京」における高速化ワークショップ

    Role(s)：Lecturer

    2015.12

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    Audience： Graduate students,　Researchesrs,　Scientific,　Company

    Type：Seminar, workshop

    宇宙プラズマの第一原理ブラソフコードの性能評価

  2. サイエンティフィック・システム研究会 科学技術計算分科会 2013年度会合「ペタからエクサへの課題」

    Role(s)：Lecturer

    サイエンティフィック・システム研究会  2013.10

    　More details

    Audience： Teachers,　Researchesrs,　Scientific,　Company,　Governmental agency

    Type：Lecture

    京コンピュータを用いた宇宙プラズマの第一原理ブラソフシミュレーション

  3. 公開講座「宇宙」

    Role(s)：Lecturer

    2010.8

    　More details

    Audience： High school students,　College students,　Graduate students,　Teachers,　Guardians,　General

    Type：Lecture

    「宇宙科学とコンピュータシミュレーション」と題して、高校生、高専生及び一般向けの公開講座を高知高専において行った。

To the head of Social Contribution.▲