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Shuichi Matsukiyo Last modified date:2020.02.06

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Undergraduate School
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Profile & Paper list .
Academic Degree
PhD in science
Country of degree conferring institution (Overseas)
Field of Specialization
Space Environmental Fluid Dynamics, space plasma physics
Total Priod of education and research career in the foreign country
Outline Activities
High energy space and astrophysical plasma phenomena like particle acceleration, collisionless shock wave, and nonlinear waves, etc., are investigated by means of theory and numerical simulation.
Recent Research Topics:
 Simulation studies on high Mach number nonstationary collisionless shocks
 Simulation studies on high energy particles produced in the solar-terrestrial system
 Simulation studies on microinstabilities and associated particle heating processes in the vicinity of collisionless shocks
 Simulation studies on cosmic ray acceleration in supernova remnant shocks
 Simulation studies on long time evolution of nonlinear waves in a relativistic pair plasma
 Research guidance to graduate and undergraduate students
 Exercise lesson on Information Processing for undergraduate students
Research Interests
  • Structure of the Earth's foreshock and particle acceleration
    keyword : Earth's bow shock, foreshock, particle acceleration
  • Experimental Study on Collisionless Shock
    keyword : laser experiment, collisionless shock
  • Structure of the heliospheric termination shock and particle acceleration
    keyword : termination shock, particle acceleration, pickup ions
  • Nonlinear wave generation and particle acceleration in a multi-ion-species plasma in the vicinity of stellar surface
    keyword : particle acceleration, multi-ion-species plasma
  • Physics of collisionless shocks
    keyword : nonstationary shock wave, anomalous dissipation, microinstability, multi-scale physics
  • Relativistic particle acceleration in space and astrophysical plasmas
    keyword : relativistic plasma, high energy particle acceleration, cosmic ray
  • Large amplitude wave-wave and wave-particle interactions in space and astrophysical plasmas
    keyword : large amplitude wave, wave-wave interaction, wave-particle interaction
Current and Past Project
  • The mechanism of electron acceleration in collisionless shock is investigated by using high accuracy spacecraft data and numerical simulation.
  • Experimental study of astrophysics using high power laser
  • Recent multi-spacecraft observations indicate that in Earth's foreshock particle acceleration occurs more efficiently than previously thought. In the foreshock field aligned beam (FAB), which is the high bulk velocity ion beam flowing away from the Earth's bow shock, is often observed. We propose a model that the waves generated by the FAB efficiently scatter high energy particles so that increase the acceleration efficiency. The model is verified by using numerical simulations and spacecraft data anayses.
  • Collisionless shocks are ubiquitous in various astrophysical, heliospheric (or solar-terrestrial), and even laboratory phenomena. The aim of this team is to formulate a common understanding regarding the latest knowledge about the initial stage of the particle acceleration (or injection) process at collisionless shocks.
    Recent gamma-ray and X-ray observations of supernova remnants have provided us with the detailed spatial and spectral structure of high-energy particles accelerated at astrophysical shocks, enabling us to discuss particle acceleration processes there. In-situ multi-spacecraft observations in the heliosphere have shown the spatio-temporal structures of shock transition region as well as the local distribution functions of thermal and non-thermal particles. In addition, laboratory astrophysics is now developing and collisionless shocks have come to be successfully reproduced in the laboratory.
    The injection problem in the diffusive shock acceleration scenario is one of the important outstanding issues. In order to understand the injection mechanism(s) at collisionless shocks, we gather our knowledge of the latest observations, simulations, and theory, not only on astrophysical and heliospheric shocks but also on laboratory shocks. It is time now for researchers in different fields to sit together and discuss current status, latest achievements and issues, in each field.
  • micro- to meso-scale structures of the termination shock and the accompanied particle acceleration
  • It is known that a high Mach number collisionless shock is often self-reforming, i.e., the shock front is cyclically formed and destroyed even though the upstream plasma parameters are steady. The self-reformation was originally found in numerical simulation studies, while its observational proof has not been established. In this study the basic features of the self-reformation is revealed by using numerical simulations. In particular we focus the phenomenon called reflected electron burst accompanied by the self-reformation and discuss how it transfers the characteristics of the self-reformation to a remote upstream region.
  • Particle simulations on nonstationary collisionless shocks
  • Microinstabilities as dissipation mechanisms in high Mach number collisionless shocks
Academic Activities
1. Local interactions between collisionless shock and plasma: Waves, multi-scale physics, particle acceleration/heating.
2. Shuichi Matsukiyo, Youichi Sakawa, Yasuhiro Kuramitsu, Taichi Morita, KENTARO TOMITA, Toseo Moritaka, Hideaki Takabe, Tohru Hada, Ryo Yamazaki, Taichi Ishikawa, Yuta Yamaura, Takayoshi Sano, Naohumi Ohnishi, Hitoki Yoneda, Nigel Woolsey, Robert Crowston, Gianluca Gregori, Michel Koenig, Yutong Li, Experiment of a spherical shock: Effect of the orientation of magnetic field on shock structure and particle acceleration
, 2014.03.
3. Shuichi Matsukiyo, Yasuhiro Kuramitsu, Youichi Sakawa, Taichi Morita, KENTARO TOMITA, Toseo Moritaka, Hideaki Takabe, Tohru Hada, Theoretical study on unmagnetized shocks in counter streaming plasmas, 2014.03.
4. Shuichi Matsukiyo, Yasuhiro Kuramitsu, Youichi Sakawa, Taichi Morita, KENTARO TOMITA, Toseo Moritaka, Hideaki Takabe, Tohru Hada, Full particle-in-cell simulations on the formation of electrostatic shock in a counter streaming plasma, 2013.03.
5. Roles of pickup ions in a collisionless shock: Parameter survey.
6. Roles of pickup ions in a collisionless shock.
7. Particle simulations on nonstationary collisionless shocks.
8. Particle simulations on nonstationary collisionless shocks.
9. Electron heating associated with microinstabilities in high Mach number shocks.
10. Numerical simulation on particle acceleration/heating in high Mach number shocks.
11. Simulation studies on acceleration/heating processes of charged particles in the vicinity of collisionless shock waves.
12. Wave-particle interactions in the vicinity of collisionless shocks in space plasmas.
13. Wave-particle interactions in a transition region of a collisionless shock.
1. Matsukiyo, S.; Noumi, T.; Zank, G. P.; Washimi, H.; Hada, T., PIC Simulation of a Shock Tube: Implications for Wave Transmission in the Heliospheric Boundary Region, The Astrophysical Journal, 10.3847/1538-4357/ab54c9, 888, 1, 11(1)-11(9), 2020.01, [URL], A shock tube problem is solved numerically by using one-dimensional full particle-in-cell simulations under the condition that a relatively tenuous and weakly magnetized plasma is continuously pushed by a relatively dense and strongly magnetized plasma having supersonic relative velocity. A forward and a reverse shock and a contact discontinuity are self-consistently reproduced. The spatial width of the contact discontinuity increases as the angle between the discontinuity normal and ambient magnetic field decreases. The inner structure of the discontinuity shows different profiles between magnetic field and plasma density, or pressure, which is caused by a non-MHD effect of the local plasma. The region between the two shocks is turbulent. The fluctuations in the relatively dense plasma are compressible and propagating away from the contact discontinuity, although the fluctuations in the relatively tenuous plasma contain both compressible and incompressible components. The source of the compressible fluctuations in the relatively dense plasma is in the relatively tenuous plasma. Only compressible fast mode fluctuations generated in the relatively tenuous plasma are transmitted through the contact discontinuity and propagate in the relatively dense plasma. These fast mode fluctuations are steepened when passing the contact discontinuity. This wave steepening and probably other effects may cause the broadening of the wave spectrum in the very local interstellar medium plasma. The results are discussed in the context of the heliospheric boundary region or heliopause..
2. Matsukiyo, S.; Akamizu, T.; Hada, T., Heavy Ion Acceleration by Super-Alfvénic Waves, The Astrophysical Journal Letters, 10.3847/2041-8213/ab58cf , 887, 1, L2(1)-L2(4), 2019.12, [URL], A generation mechanism of super-Alfvénic (SPA) waves in multi-ion species plasma is proposed, and the associated heavy ion acceleration process is discussed. The SPA waves are thought to play important roles in particle acceleration since they have large wave electric fields because of their high phase velocity. It is demonstrated by using full particle-in-cell simulations that large amplitude proton cyclotron waves, excited due to proton temperature anisotropy, nonlinearly destabilize SPA waves through parametric decay instability in a three-component plasma composed of electrons, protons, and α particles. At the same time, α cyclotron waves get excited via another decay instability. A pre-accelerated α particle resonates simultaneously with the two daughter waves, the SPA waves and the α cyclotron waves, and it is further accelerated perpendicular to the ambient magnetic field. The process may work in astrophysical environments where a sufficiently large temperature anisotropy of lower mass ions occurs..
3. Shuichi Matsukiyo, 蔵満康浩, KENTARO TOMITA, Collective scattering of an incident monochromatic circularly polarized wave in an unmagnetized non-equilibrium plasma, Journal of Physics: Conference Series, 10.1088/1742-6596/688/1/012062, 688, 012062(1)-012062(4), Vol.688, 012062, 2016.04, [URL].
4. Shuichi Matsukiyo, 松本洋介, Electron Acceleration at a High Beta and Low Mach Number Rippled Shock, Journal of Physics: Conference Series, 10.1088/1742-6596/642/1/012017, 642, 012017(1)-012017(7), Vol.642, 012017, 2015.09, [URL].
5. Shuichi Matsukiyo, Manfred Scholer, Simulations of pickup ion mediated quasi-perpendicular shocks: Implications for the heliospheric termination shock, Journal of Geophysical Research, 10.1002/2013JA019654, 119, 2014.04.
6. S. Matsukiyo, and M. Scholer, Dynamics of energetic electrons in nonstationary quasi-perpendicular shocks, Journal of Geophysical Research, 10.1029/2012JA017986, 117, A11, A11105, vol.117, A11, A11105, 2012.11, [URL].
7. Shuichi Matsukiyo, Yutaka Ohira, Ryo Yamazaki, Takayuki Umeda, Relativistic Electron Shock Drift Acceleration in Low Mach Number Galaxy Cluster Shocks, Astrophysical Journal, 10.1088/0004-637X/742/1/47, 742, Issue 1, article id. 47, vol.742, article id. 47, 2011.11, [URL].
8. S. Matsukiyo, and M. Scholer, Microstructure of the heliospheric termination shock: Full particle electrodynamic simulations, Journal of Geophysical Research, 10.1029/2011JA016563, 116, A8, A08106, vol.116, A8, A08106, 2011.08, [URL].
9. Shuichi Matsukiyo, Mach number dependence of electron heating in high Mach number quasiperpendicular shocks, Physics of Plasmas, 10.1063/1.3372137, 17, 4, 042901, Vol.17, Issue 4, pp.042901, 2010.04, [URL].
10. Shuichi Matsukiyo, Tohru Hada, Relativisitic particle acceleration in developing Alfven turbulence, Astrophysical Journal, 10.1088/0004-637X/692/2/1004, 692, Issue 2, 1004-1012, vol.692, pp.1004-1012, 2009.02, [URL].
11. Shuichi Matsukiyo, Manfred Scholer, David Burgess, Pickup protons at quasi-perpendicular shocks: full particle electrodynamic simulations, Annales Geophysicae, 25, Issue 1, 283-291, vol.25, Issue 1, pp.283-291, 2007.01, [URL].
12. Shuichi Matsukiyo, Manfred Scholer, On reformation of quasi-perpendicular collisionless shocks, Advances in Space Research, 10.1016/j.asr.2004.08.012, 38, Issue 1, 57-63, vol. 38, Issue 1, pp.57-63, 2006.09, [URL].
13. Shuichi Matsukiyo, Manfred Scholer, On microinstabilities in the foot of high Mach number perpendicular shocks, Journal of Geophysical Research, 10.1029/2005JA011409, 111, Issue A6, CiteID A06104, vol. 111, Issue A6, CiteID A06104, DOI 10.1029/2005JA011409, 2006.06, [URL].
14. Shuichi Matsukiyo, Rudolf Treumann, Manfred Scholer, Coherent waveforms in the auroral upward current region, Journal of Geophysical Research, 10.1029/2004JA010477, 109, Issue A6, CiteID A06212, Volume 109, Issue A6, CiteID A06212, 2004.06, [URL].
15. Shuichi Matsukiyo, Manfred Scholer, Modified two-stream instability in the foot of high Mach number quasi-perpendicular shocks, Journal of Geophysical Research, 10.1029/2003JA010080, 108, Issue A12, SMP 19-1, Volume 108, Issue A12, pp. SMP 19-1, CiteID 1459, DOI 10.1029/2003JA010080, 2003.12, [URL].
16. Shuichi Matsukiyo, Tohru Hada, Parametric instabilities of circularly polarized Alfvén waves in a relativistic electron-positron plasma, Physical Review E,, 10.1103/PhysRevE.67.046406, 67, Issue 4, id. 046406, vol. 67, Issue 4, id. 046406, 2003.04, [URL].
17. Shuichi Matsukiyo, Tohru Hada, Nonlinear evolution of electromagnetic waves driven by the relativistic ring distribution, Physics of Plasmas, 10.1063/1.1431593, 9, Issue 2, 649-661, Volume 9, Issue 2, February 2002, pp.649-661, 2002.02, [URL].
18. Shuichi Matsukiyo, Tohru Hada, Mitsuhiro Nambu, Jun-Ichi Sakai, Comparison between the Landau and Cyclotron Resonances in the Electron Beam-Plasma Interactions, Journal of Physical Society of Japan, 10.1143/JPSJ.68.1049, 68, Issue 3, 1049-1054, Vol.68, Issue 3, pp.1049-1054, 1999.03, [URL].
1. Shuichi Matsukiyo, Tomoki Noumi, Haruichi Washimi, Tohru Hada, Gary P. Zank, Microstructure of heliospheric boundary and implication for the origin of compressible turbulence in VLISM, 17th Annual International Astrophysics Conference, 2018.03, [URL].
2. Shuichi Matsukiyo, Fumiko Otsuka, PIC simulation of quasi-parallel shock: Foreshock structure, EGU Meeting 2017, 2017.04, [URL].
3. Shuichi Matsukiyo, Roles of microinstabilities in collisionless shocks, 6th East-Asia School and Workshop on Laboratory, Space, Astrophysical Plasmas, 2016.07, [URL].
4. Shuichi Matsukiyo, PIC Simulation of High Beta and Low Mach Number Astrophysical Shocks: Microstructures and Electron Acceleration, 5th East-Asia School and Workshop on Laboratory Space and Astrophysical plasmas, 2015.08, [URL].
5. Shuichi Matsukiyo, Electron acceleration at a high beta shock, 14th Annual International Astrophysics Conference, 2015.04, [URL].
6. 松清 修一, Collisionless shocks in magnetized and unmagnetized plasmas: PIC simulation and laser experiment, 大阪大学レーザーエネルギー学研究センター日米ワークショップ, 2014.02.
7. Theoretical studies on the production of high Mach number collisionless shocks.
8. 松清 修一, PIC simulations of the termination shock, 8th European Workshop on Collisionless shocks, 2013.06, [URL].
9. 松清 修一, Manfred Scholer, PIC simulations on the termination shock: Microstructure and electron acceleration, 2013 AGU Meeting of Americas, 2013.05, [URL], The ability of the termination shock as a particle accelerator is totally unknown. Voyager data and recent kinetic numerical simulations revealed that the compression ratio of the termination shock is rather low due to the presence of pickup ions, i.e., the termination shock appears to be a weak shock. Nevertheless, two Voyager spacecraft observed not only high energy ions called termination shock particles, which are non-thermal but less energetic compared to the so-called anomalous cosmic rays, but also high energy electrons. In this study we focus especially on microstructure of the termination shock and the associated electron acceleration process by performing one-dimensional full particle-in-cell (PIC) simulations for a variety of parameters. For typical solar wind parameters at the termination shock, a shock potential has no sharp ramp with the spatial scale of the order of electron inertial length which is suitable for the injection of anomalous cosmic ray acceleration. Solar wind ions are not so much heated, which is consistent with Voyager spacecraft data. If a shock angle is close to 90 deg., a shock is almost time stationary or weakly breathing when a relative pickup ion density is 30%, while it becomes non-stationary if the relative pickup ion density is 20%. When the shock angle becomes oblique, a self-reformation occurs due to the interaction of solar wind ions and whistler precursors. Here, the shock angle is defined as the angle between upstream magnetic field and shock normal. For the case with relatively low beta solar wind plasma (electron beta is 0.1 and solar wind ion temperature equals to electron temperature), modified two-stream instability (MTSI) gets excited in the extended foot sustained by reflected pickup ions, and both solar wind electrons and ions are heated. If the solar wind plasma temperature gets five times higher, on the other hand, the MTSI is weakened and the pre-heating of the solar wind plasma in the extended foot is suppressed. Although the electron acceleration rate is not so much dependent on these microstructures, it depends on the shock angle. The shock drift acceleration efficiently occurs for oblique shocks..
10. Microstructure of the Termination Shock: Full PIC Simulation, [URL].
11. Full Particle Simulation on Microstructure of Heliospheric Termination Shock, [URL].
12. Full Particle-In-Cell Simulation on Collisionless Shocks:Electron and Ion Dynamics in the Transition Region, [URL].
13. Nonthermal electrons produced by supercritical quasi-perpendicular shocks, [URL].
14. Electron Heating through microinstabilities in High Mach Number Quasi-Perpendicular Shocks, [URL].
15. Electron heating through microinstabilities in high Mach number quasi-perpendicular shocks, [URL].
16. Relativistic particle acceleration in developing Alfven turbulence, [URL].
17. Relativistic particle acceleration in coherent Alfven waves through parametric instabilities.
18. Relativistic particle acceleration by coherent Alfven waves upstream of collisionless shocks.
19. PIC simulations of quasi-perpendicular shocks: Roles of modified two-stream instability in particle heating, acceleration, and self-reformation processes, [URL].
20. Roles of Modified Two-Stream Instability in Supercritical Shock Waves, [URL].
21. Shock angle dependence of nonstationary behaviour of quasi-perpendicular shocks.
22. Energy dissipation through microinstabilties in the foot of high Mach number quasi-perpendicular shocks, [URL].
23. Microinstabilities in collisionless shocks: recent simulation results.
24. Reformation of quasi-perpendicular shocks with realistic ion to electron mass ratio.
Membership in Academic Society
  • Asia Oceania Geosciences Society
  • European Geosciences Union
  • Japan Geoscience Union
  • American Geophysical Union
  • Society of Geomagnetism and Earth, Planetary and Space Sciences
  • Tanakadate Award
  • Obayashi Early Career Scientist Award
Educational Activities
Exercise lesson on information processing technique and computer programming.
Research guidance to graduate and undergraduate students: Students experience a process getting over the problem which has not been resolved so far. They need to master basic knowledge on (plasma) physics as well as digital techniques. Finally, students will have ability to set up a problem and to solve it by themselves.