Shuichi Matsukiyo | Last modified date：2021.06.30 |

Associate Professor /
Space Environmental Fluid Dynamics /
Department of Advanced Environmental Science and Engineering /
Faculty of Engineering Sciences

**Presentations**

1. | Numerical simulation on GCR invading process into the heliosphere. |

2. | Diffusion process of energetic ions through the interactions with ULF waves in terrestrial foreshock. |

3. | Shuichi Matsukiyo, Kotaro Yoshida, Haruichi Washimi, Gary P. Zank, Kinetic properties of heliospheric boundary, AGU Fall Meeting 2020, 2020.12, [URL], In the heliospheric boundary region matter and energy are extensively transported and/or converted between the heliosphere and the local interstellar space. This region has been explored in-situ by Voyager spacecraft in this century. Voyager spacecraft revealed a lot of features of the two important discontinuities, termination shock and heliopause, as well as unexpected properties of high energy particles in the boundary region. Some of the features have been still not well understood. We first review our full particle-in-cell simulation studies to discuss kinetic properties of the two discontinuities. Then, we further discuss our recent work on the effect of global structure of the heliosphere in the cosmic ray invasion process into the heliosphere.. |

4. | Proton Flux Response in the South Atlantic Anomaly due to Inductive Electric Field, [URL]. |

5. | Electron scattering and acceleration at quasi-perpendicular shock: Comparison between PIC simulation and MMS observation, [URL]. |

6. | The DSA with two crossing shocks, [URL]. |

7. | High power laser experiment of collisionless magnetized shock: Effect of ambient magnetic field strength , [URL]. |

8. | Numerical simulation for high power laser experiment of collisionless shock: Effect of multi ion species, [URL]. |

9. | Classification of shocklets using convolutional neural network, [URL]. |

10. | Simulation study on the invading process of galactic cosmic rays into the heliosphere , [URL]. |

11. | Gekko XII experiment and numerical simulation on magnetized collisionless shock, [URL]. |

12. | F. Otsuka, S. Matsukiyo, M. Oka, Stochastic acceleration of electrons at collisionless quasi-perpendicular shocks: PIC simulation, 4th Asia-Pacific Conference on Plasma Physics, 2020.10, [URL]. |

13. | K. Yoshida, K. Shimokawa, S. Matsukiyo, H. Washimi, T. Hada, Numerical simulation of invading process of galactic cosmic rays into the heliosphere, 4th Asia-Pacific Conference on Plasma Physics, 2020.10, [URL]. |

14. | S. Matsukiyo, K. Yoshida, K. Shimokawa, H. Washimi, G. P. Zank, M. Scholer, T. Hada, Heliospheric boundary: Kinetic structure, cosmic ray property, 4th Asia-Pacific Conference on Plasma Physics, 2020.10, [URL], Heliosphere is a bubble occupied by the solar wind plasma and magnetic field in the local interstellar space. Matter and energy are actively transported and/or converted in the boundary region between the heliosphere and the local interstellar space. This region has been explored in-situ by Voyager spacecraft in this century1-18. Voyager spacecraft revealed a lot of features, some of which have been still unresolved, such as complex structures of two important discontinuities, unexpected properties of high energy particles, etc. In this study we first focus on the kinetic structures of the termination shock and the heliopause. Using particle-in-cell simulation, kinetic structure of the transition region of these discontinuities are investigated. In the termination shock the roles of pickup ions are examined carefully19-22. Kinetic structure of the heliopause influenced by the termination shock is also studied3. In the second part of this study the effect of global structure of the heliosphere in the cosmic ray invasion process is considered. It has been unknown how galactic cosmic rays enter and reach deep inside the heliosphere. To understand the cosmic ray invasion process in the level of particle trajectory, we perform a test particle simulation in the global electromagnetic structure of the heliosphere reproduced by using high resolution 3D MHD simulation. A number of characteristic trajectories of different energy cosmic ray particles are reported.. |

15. | S. Matsukiyo, Experimental investigations on the shock reformation, Workshop on laboratory astrophysics: Novel development in nonlinear plasma physics with lasers, 2020.09, [URL]. |

16. | High power laser experiment on the shock self-reformation, [URL]. |

17. | 岡光夫、大塚史子、松清修一、T.Phan, MMS team The, Electron scattering and acceleration by whistler waves at collisionless shocks, JpGU-AGU 2020 meeting, 2020.07, [URL]. |

18. | 大塚史子、松清修一、岡光夫, PIC simulation of electron acceleration at quasi-perpendicular collisionless shock: Application to earth's bow shock, JpGU-AGU 2020 meeting, 2020.07, [URL]. |

19. | S. Matsukiyo, T. Higuchi, H.Murakami, Y. Sakawa, T. Morita, K.Tomita, R.Yamazaki, T.Sano, Y.Kuramitsu, S.-J. Tanaka, N.Ishizuka, S.Kakuchi, S.Sei, K.Sugiyama, M.Ota, S.Egashira, T.Izumi, K.Sakai, T.Minani, H.Nishioka, M.Takagi, T.Kojima, K.Aihara, S.Kanbayashi, S.Tomita, Y.Nakagawa, T.Nishimoto, M.Takano, Gekko XII experiment on magnetized collisionless shock, JpGU-AGU 2020 meeting, 2020.07, [URL]. |

20. | Shuichi Matsukiyo, Yosuke Matsumoto , Electron acceleration at a high beta shock, AGU Fall Meeting 2019, 2019.12, [URL]. |

21. | Experimental study of self-reformation of collisionless shock using high power laser. |

22. | S. Matsukiyo, Kinetic radial structure of heliospheric boundary, 3rd Asia-Pacific Conference on Plasma Physics, 2019.11, [URL], Kinetic radial structure of heliospheric boundary Abstract: The kinetic structure of the heliospheric boundary region is investigated using one-dimensional full PIC (Particle-In-Cell) simulations. A shock tube problem is numerically solved under the condition that a relatively tenuous and weakly magnetized plasma, mimicking the solar wind (SW) plasma, is continuously pushed by a relatively dense and strongly magnetized plasma, mimicking the interstellar (IS) plasma, having supersonic relative velocity. A forward and a reverse shock, corresponding to the SW termination shock and the IS bow shock, and a contact discontinuity, to the heliopause, are self-consistently reproduced. The spatial width of the heliopause increases as the angle between the discontinuity normal and ambient magnetic field decreases. The inner structure of the heliopause 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 turbulence in the relatively dense plasma, corresponding to the outer heliosheath, is compressible and propagating away from the heliopause, although the turbulence in the relatively tenuous plasma, corresponding to the inner heliosheath, contains both compressible and incompressible fluctuations. The source of the compressible turbulence in the outer heliosheath is in the inner heliosheath. Only compressible fast mode fluctuations generated in the inner heliosheath are transmitted through the heliopause and propagate in the outer heliosheath. The results are discussed in the context of recent observations by Voyager spacecraft.. |

23. | 2D structure of pickup ion mediated shocks, [URL]. |

24. | Pitch angle diffusion of electrons by oblique whistler waves, [URL]. |

25. | Electron acceleration through synchrotron maser instability in a relativistic electron-proton plasma , [URL]. |

26. | High power laser experiment on shock reformation, [URL]. |

27. | One-dimensional PIC simulation of shock reformation reproduced in high power laser experiment, [URL]. |

28. | Numerical simulation of a collision between space elevator and space debris, [URL]. |

29. | Identification of Shocklets using Convolutional Neural Networks (CNNs) , [URL]. |

30. | Short-Term Variations of Proton Flux in South Atlantic Anomaly due to Solar Storm Conditions, [URL]. |

31. | Gekko XII experiment intended to evidence self-reformation of collisionless shock. |

32. | Shuichi Matsukiyo, Acceleration of relativistic electrons at a high beta shock, 10th Korean Astrophysics Workshop: Astrophysics of high-beta plasma in the ICM, 2019.07, [URL], A high beta shock has not been paid much attention from the aspect of particle acceleration, since it is a relatively weak shock so that its structure is more or less laminar and steady where the activities of waves are generally thought to be low. In space, on the other hand, a number of high beta shocks are observed and some of them indicate the evidence of particle acceleration. We found that relativistic shock drift acceleration followed by reflection efficiently works at such a high beta shock by using one-dimensional full particle-in-cell (PIC) simulation. This mechanism is suppressed, however, when the effect of higher dimension is taken into account due to the rippled structure of shock surface. We further consider the presence of halo electrons which are the non-thermal component often observed also in the solar wind. Then, it is found that the halo electrons are preferentially accelerated and reflected. Its efficiency appears to be increased due to the rippled structure.. |

33. | Radial structure of heliospheric boundary region, [URL]. |

34. | Shuichi Matsukiyo, Gary P. Zank, Haruichi Washimi, Tohru Hada, Kinetic scale radial structure of the heliopause, 18th Annual International Astrophysics Conference, 2019.02, [URL], The kinetic structure of the heliospheric boundaries is investigated using one-dimensional full PIC (Particle-In-Cell) simulations. Both the termination shock and the heliopause are simultaneously reproduced in the simulation. The spatial scale of the heliopause increases as the angle between the heliopause normal and local magnetic field (referred to as the normal angle, hereafter) becomes increasingly oblique. The total pressure, including the plasma pressure and magnetic pressure, at the heliopause is not constant when the normal angle is oblique in contrast to predictions based on MHD theory. In the oblique case, the solar wind plasma and interstellar plasma are able to inter-penetrate by moving along the local magnetic field. Since their bulk velocities along the magnetic field differ from each other, the distributions overlap in phase space so that the effective local plasma pressure parallel to the magnetic field is enhanced. This results in an increase that resembles a hump in the density and parallel pressure of the local plasma, which is not seen in magnetic field.. |

35. | S. Matsukiyo, K. Shimokawa, H. Washimi, T. Hada, G. P. Zank, Test particle simulation of CR invasion into the heliosphere, ISEE symposium: Recent progress in heliospheric physics by direct measurements of unexplored space plasmas, 2019.02, [URL]. |

36. | High power laser experiment on collisionless shock, [URL]. |

37. | Two dimensional structure of a collisionless perpendicular shock mediated by hot ions, [URL]. |

38. | Numerical simulation of the transport process of galactic cosmic rays into the heliosphere, [URL]. |

39. | Relation of solar wind current sheet and VLISM turbulence, [URL]. |

40. | Data analysis of collisionless shock experiment using high power laser, [URL]. |

41. | Nonlinear evolution of Alfven waves in the DNLS system, [URL]. |

42. | Dynamics of the space elevator under unstable conditions, [URL]. |

43. | Variations of South Atlantic Anomaly due to Space Weather Conditions, [URL]. |

44. | S. Matsukiyo, Microstructure of high beta quasi-perpendicular shock and associated electron dynamics, 2nd Asia-Pacific Conference on Plasma Physics, 2018.11, [URL], Electron acceleration in a high beta and low Mach number quasi-perpendicular collisionless shock is investigated by using one- and two-dimensional full particle-in-cell simulations. In contrast to low beta or high Mach number shocks, relativistic shock drift acceleration followed by reflection is observed in one-dimensional simulation. However, the reflection is suppressed due to the effect of shock surface rippling in two-dimensional simulations, while less efficient reflection is confirmed when shock angle is deviated from perpendicular (The shock angle is defined as the angle between shock normal and upstream magnetic field.). Structure of the shock transition region is much more complicated than previously expected, in spite of the high beta and low Mach number situation. Not only ion scale fluctuations, including the ripple, but also electron scale fluctuations are seen. Among these, downstream fluctuations are dominated by electromagnetic ion cyclotron instability and/or mirror instability, electron scale fluctuations in the overshoot (foot) are due to whistler instability (modified two-stream instability). Relative importance of the instabilities changes with the shock angle. We further studied the behavior of halo electrons whose temperature is one order higher than background upstream electrons. By assuming that relative density of the halo electrons is sufficiently low so that their dynamics do not affect the behavior of electromagnetic fields, the halo electrons are treated as test particles. We found that the halo electrons are preferentially reflected after being accelerated through the shock drift mechanism even if the shock surface ripple is present. They are also heated more efficiently than the background electrons.. |

45. | Invading process of galactic cosmic rays into the heliosphere. |

46. | S.Matsukiyo, Y.Matsumoto, Y.Fujita, Acceleration of halo electrons at a high beta low Mach number quasi-perpendicular shock, 12th International Conference on High Energy Density Laboratory Astrophysics, 2018.05, [URL]. |

47. | PIC simulation of high beta shocks: Microstructure and electron acceleration, [URL]. |

48. | Precise measurement of multiscale structures of collisionless shocks in a plasma. |

49. | PIC simulation of electron acceleration by whistler waves at the Earth’s foreshock. |

50. | Internal structure of high beta super critical shock. |

51. | Thomson scattering measurement of foreshock plasma. |

52. | 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], Microstructure of heliospheric boundary is investigated by using full PIC (Particle-In-Cell) simulations. Both the termination shock and the heliopause are simultaneously reproduced by using the PIC simulation, although system size is very limited and a strong assumption of one-dimensionality is imposed. Spatial scale of the heliopause increases as the angle between the heliopause normal and interstellar magnetic field becomes oblique. The downstream of the termination shock, the region between the termination shock and the heliopause, contains large amplitude magnetic as well as density fluctuations. The VLISM region also contains some fluctuations in magnetic field and density. We investigated the origin and the characteristics of those fluctuations. The density fluctuations show partly positive and partly negative correlations with the magnetic fluctuations in the downstream of the termination shock. The positively correlated fluctuations are produced in the shock front through the self-reformation process, while the negatively correlated ones are generated through mirror instability. On the other hand, the fluctuations in the VLISM show only positive correlation between magnetic and density fluctuations. Further, the fluctuations propagate from the heliopause to the VLISM, which implies that those fluctuations are originated from the heliosphere.. |

53. | Fumiko Otsuka, Shuichi Matsukiyo, Arpad Kis, Tohru Hada, Effect of upstream ULF waves on the energetic ion diffusion at the earth’s foreshock: Theory, Simulation, and Observations, AGU Fall Meeting 2017, 2017.12, [URL]. |

54. | Shuichi Matsukiyo, Yosuke Matsumoto, Yutaka Fujita, Energization of halo electrons at a high beta low Mach number quasi-perpendicular shock, AGU Fall Meeting 2017, 2017.12, [URL]. |

55. | Electron energization in high beta low Mach number quasi-perpendicular shock, [URL]. |

56. | Electron acceleration at Earth’s foreshock: One-dimensional PIC simulation, [URL]. |

57. | Investigation of Electron Acceleration through the Interaction of between the Earth’s Bow Shock and an Interplanetary Shock, [URL]. |

58. | Numerical simulation of the transport process of cosmic rays into the heliosphere , [URL]. |

59. | One-dimensional PIC simulation of boundary region of heliosphere, [URL]. |

60. | Test particle simulation of Anomalous cosmic ray transport in MHD turbulence, [URL]. |

61. | Numerical simulation of collective Thomson scattering in a magnetized plasma in high power laser experiment, [URL]. |

62. | Virtual collective Thomson scattering measurement for collisionless shock experiment at ILE , [URL]. |

63. | Microinstabilities in the transition region of a supercritical perpendicular shock, [URL]. |

64. | Shuichi Matsukiyo, Fumiko Otsuka, Kento Nakanishi, Arpad Kis, Tohru Hada, Effect of Field-Aligned-Beam In Parallel Diffusion of Energetic Particles in Earth's Foreshock, AOGS2017, 2017.08, [URL]. |

65. | Precise measurement of multiscale structures of collisionless shock. |

66. | Test particle simulation of invading process of galactic cosmic rays into the heliosphere , [URL]. |

67. | Electron acceleration via interaction between the Earth's bow shock and an interplanetary shock, [URL]. |

68. | Landau resonance between electrons and lower-hybrid waves in the inner magnetosphere, [URL]. |

69. | Upstream wave evolution, particle diffusion and acceleration in the earth's foreshock: One-dimensional PIC simulation , [URL]. |

70. | Shuichi Matsukiyo, Fumiko Otsuka, PIC simulation of quasi-parallel shock: Foreshock structure, EGU Meeting 2017, 2017.04, [URL], Electromagnetic structure of a quasi-parallel shock is highly complex. From the viewpoint of numerical kinetic simulation, quite large simulation domain is necessary to reproduce a foreshock region where some particles are back streaming almost freely along the ambient magnetic field. This may be a main reason that full particle-in-cell (PIC) simulations of a quasi-parallel shock have been seldom performed, although there are only a few examples. Here, both ion and electron scale structures of the foreshock in a quasi-parallel shock are investigated by using one-dimensional full PIC simulation with sufficiently large system size (= 2500 ion inertial lengths). The shock parameters are as follows. The Alfven Mach number is 6.6, upstream ion and electron betas are both 0.5, and the shock angle is 20 deg. The ion to electron mass ratio is 64, the ratio of electron plasma to cyclotron frequency is 12.5. Well developed large amplitude MHD waves, evolution of back streaming ion distribution function, electron scale structure grown in the MHD scale structure, and dynamics of high energy particles are discussed.. |

71. | Istvan Lemperger, Arpad Kis, Viktor Wesztergom, Michel Menvielle, Sándor Szalai, Attila Novák, Tohru Hada, Shuichi Matsukiyo, Ahmed Mohsen Lethy, Investigation of Magnetotelluric Source Effect Based on Twenty Years of Telluric and Geomagnetic Observation, AGU Fall Meeting 2016, 2016.12, [URL]. |

72. | Masaru Nakanotani, Shuichi Matsukiyo, Tohru Hada, Christian Xavier Mazelle, Ion acceleration and its effect in shock-shock interaction, AGU Fall Meeting 2016, 2016.12, [URL]. |

73. | Shuichi Matsukiyo, Kento Nakanishi, Fumik Otsuka, Arpad Kis, Istvan Lemperger, Tohru Hada, Effect of field-aligned-beam in parallel diffusion of energetic particles in the Earth's foreshock, AGU Fall Meeting 2016, 2016.12, [URL]. |

74. | , [URL]. |

75. | Generation of electron anisotropies at earth’s magnetotail, [URL]. |

76. | Effect of the FAB on the upstream wave excitation in the Earth’s bow shock: One-dimensional PIC simulation, [URL]. |

77. | Test particle simulation on generation of plasma acceleration region by external rotating magnetic ﬁeld, [URL]. |

78. | Numerical simulation of virtual Thomson scattering measurement of non-equilibrium laboratory plasmas, [URL]. |

79. | Numerical simulation of plasma detachment, [URL]. |

80. | Analysis of magnetohydrodynamic turbulence in space using data obtained by multi-spacecraft experiments , [URL]. |

81. | Structure of Electrostatic Shocks produced in High Power Laser Experiments, [URL]. |

82. | Shuichi Matsukiyo, Roles of microinstabilities in collisionless shocks, 6th East-Asia School and Workshop on Laboratory, Space, Astrophysical Plasmas, 2016.07, [URL], In a collisionless shock microinstabilities play important roles. They heat an incoming plasma to provide necessary dissipation in a transition region. They are sometimes able to directly produce non-thermal particles. Furthermore, they produce a scatterer of the non-thermal particles in the context of diffusive shock acceleration (DSA). We review the above mentioned roles of microinstabilities in some cases of quasi-perpendicular shocks from the viewpoint of full particle-in-cell simulation. First, we focus on the instabilities generated in the so-called foot region, which is produced by the ions specularly reflected at the shock (ramp). The reflected ions become a beam in terms of the incoming plasma so that some microinstabilities get excited. Depending on the shock parameters a variety of instabilities are generated. Here, we introduce electron thermal Mach number, Mte, defined as the upstream flow velocity normalized to electron thermal velocity, which is proportional to Alfven Mach number divided by the square root of electron beta. When the Mach number is low, Mte ≲ 1, as in the Earth’s bow shock, electron cyclotron-drift instability, and modified two-stream instability are dominantly generated. These instabilities contribute to electron as well as ion heating. For higher Mach numbers, Mte >> 1, Buneman instability gets excited. The resultant large amplitude waves trap some electrons which are accelerated by the convection electric field to non-thermal energy while being trapped. On the other hand, when Mte < cosBn (B2/B1)1/2, non-negligible amount of electrons are mirror reflected at a shock. The reflected electrons form a foreshock. In the foreshock resonant and non-resonant instabilities are generated. The latter is also called electron firehose instability and efficiently scatter the reflected electrons. The waves play crucial roles in injection of non-thermal electrons into DSA.. |

83. | Precise measurement of multiscale structures of collisionless shock, [URL]. |

84. | Numerical simulation of collective Thomson scattering in laboratory astrophysics, [URL]. |

85. | Microinstabilities in a supercritical perpendicular shock revisited, [URL]. |

86. | Collective Thomson scattering measurement in high power laser experiment of collisionless shock . |

87. | Thomson scattering measurement of foreshock plasma. |

88. | 中野谷賢, Shuichi Matsukiyo, Christian Mazelle, T. Hada (10/32), Electron acceleration in shock-shock interaction: Simulations and observations, AGU fall meeting 2015, 2015.12, [URL]. |

89. | Shuichi Matsukiyo, Takayuki Umeda, Electron scale instabilities in the foot of a perpendicular shock, AGU fall meeting 2015, 2015.12, [URL]. |

90. | Thomson scattering measurement in high power laser experiment of collisionless shock. |

91. | High power laser experiment on collisionless shock: Potential of Thomson scattering measurement, [URL]. |

92. | Acceleration of charged particles by parallel and anti-parallel propagating Alfven waves, [URL]. |

93. | Effect of the FAB on the diffusive process upstream of the bow shock: Test particle simulation , [URL]. |

94. | Theoretical study of collective Thomson scattering in a non-equilibrium plasma, [URL]. |

95. | Electron acceleration by lower-hybrid waves near the geomagnetic equator: One-dimensional test particle simulation study, [URL]. |

96. | Effect of the FAB on the diffusive process upstream of the bow shock: Comparison between observation and test particle simulation , [URL]. |

97. | Microinstabilities in the transition region of collisionless shockes. |

98. | Shuichi Matsukiyo, Collective Thomson scattering diagnostics in non-equilibrium plasma: Application to high power laser experiment, 2015 URSI-Japan Radio Science Meeting, 2015.09, [URL]. |

99. | 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]. |

100. | Modeling of Particle Acceleration in Shock-Shock Interaction , [URL]. |

101. | Electron acceleration at high beta low Mach number collisionless shock, [URL]. |

102. | Shuichi Matsukiyo, Electron acceleration at a high beta shock, 14th Annual International Astrophysics Conference, 2015.04, [URL]. |

103. | 山崎了, 正治圭崇, 河村有志郎, 大平豊, 冨田沙羅, 坂和洋一, 高部英明, 佐野孝好, 森高外征雄, 原由希子, 近藤さらな, Shuichi Matsukiyo, 森田 太智, KENTARO TOMITA, 米田仁紀, 蔵満康浩, Generation of Magnetized Collisionless Shocks with High-Power Lasers, Conference on Laser Energetics 2015, 2015.04, [URL]. |

104. | 中野谷賢, Shuichi Matsukiyo, 羽田 亨, 坂和洋一, 蔵満康浩, 森田 太智, 藤野亮介, 久保総一郎, 佐野孝好, 森高外征雄, 原由希子, 山崎了, 高部英明, High power laser experiment of planar collisionless shocks, Conference on Laser Energetics 2015, 2015.04, [URL]. |

105. | Precise measurement of multi-scale structures of collisionless shocks in a plasma. |

106. | PIC simulation on multi-scale physics of collisionless shocks in high power laser experiment. |

107. | Laser experiment of spherical shocks in magnetized plasma. |

108. | Shuichi Matsukiyo, Yosuke Matsumoto, Microphysics of a multidimensional high beta low Mach number shock, AGU fall meeting 2014, 2014.12, [URL], It is generally thought that a high beta shock is weak so that its structre is relatively laminar and stationary. Such low Mach number shocks have not been paid much attention in terms of particle acceleration. However, Voyager spacecraft revealed that the fluxes of not only the non-thermal ions, which are called as the termination shock particles, but also of the non-thermal electrons are enhanced at the crossings of the termination shock. The heliospheric termination shock has a high effective beta due to the presence of pickup ions which are the component having rather high thermal energy. Radio synchrotron emissions from relics of galaxy cluster mergers imply the presence of relativistic electrons accelerated in merger shocks. A plasma beta of such a merger shock is also thought to be rather high so that the merger shocks are usually assumed to have low Mach numbers. These observational facts imply that even a low Mach number shock can be a good accelerator of non-thermal particles. Here, we perform two-dimensional full particle-in-cell simulation to study microstructure of a high beta low Mach number shock and the associated electron acceleration process. Although the effective magnotosonic Mach number is rather low, ~2.6, the structure of the transition region is highly complex. Ion and electron scale structures coexist. Furthermore, some electrons are accelerated to high energy. We will discuss the mechanisms of producing those two-dimensional microstructures and high energy electrons.. |

109. | Takauki Umeda, Yoshitaka Kidani, Shuichi Matsukiyo, Ryo Yamazaki, Reformation and microinstabilities at perpendicular collisionless shocks, AGU fall meeting 2014, 2014.12, [URL]. |

110. | , [URL]. |

111. | Multidimensional Structure of a High Beta Low Mach Number Shock and Particle Acceleration, [URL]. |

112. | Examination of plasma diagnostics for experimental study on collisionless shocks. |

113. | Collective Thomson scattering in non-equilibrium plasma: Application to high power laser experiment. |

114. | Experimental study of collisionless shocks : Verification of jump conditions. |

115. | Shuichi Matsukiyo, PIC simulation of heliospheric termination shock, Taiwan-Japan Workshop 2014: Laboratory Astrophysics with Ultra Intense Lasers, 2014.10, [URL]. |

116. | 中野谷賢, Shuichi Matsukiyo, Tohru Hada, Numerical Experiment of Two Colliding Shocks, AOGS 11th Annual Meeting, 2014.07, [URL]. |

117. | Shuichi Matsukiyo, Yosuke Matsumoto, 2D Structure of a High Beta Shock and the Associated Particle Acceleration, AOGS 11th Annual Meeting, 2014.07, [URL], It is generally thought that a high beta shock is relatively laminar and stationary. The heliospheric termination shock has a rather high effective beta due to the presence of pickup ions. The pickup ions are the component having rather high thermal energy and their relative density in the solar wind near the termination shock is estimated as 20-30%. Hence, the termination shock may be a more moderate shock than considered before. Nevertheless, Voyager 2 spacecraft revealed that the fluxes of not only the non-thermal ions, which are called as the termination shock particles, but also of the non-thermal electrons are enhanced at the crossings of the termination shock. So far, on the other hand, the electron acceleration at the termination shock has not been studied well. Here, we perform two-dimensional full particle-in-cell simulation to study microstructure of a high beta shock and the associated electron acceleration process. Instead of including the pickup ions explicitly, a high temperature upstream flow with a single Maxwellian ion component is assumed in the simulation. Although the shock is more or less time stationary, the structure of the transition region is rather complex. Furthermore, some electrons are accelerated to high energy. We will discuss the mechanisms of producing those two-dimensional microstructures and high energy electrons. . |

118. | Colliding Two Oblique Shocks: Shock Structures and Particle Acceleration, [URL]. |

119. | Current status and issues of a study on collisionless shocks by using laser experiment, [URL]. |

120. | Experimental study on collisionless shocks with high-power laser system ”Gekko-XII”, [URL]. |

121. | Weibel instability mediated collisionless shock generation using large-scale laser systems, [URL]. |

122. | 2D Full Particle-In-Cell Simulation on a High Beta Collisionless Shock and Particle Acceleration, [URL]. |

123. | 松清 修一, Microstructure of shock transition region in space and laboratory plasmas, ISSI team meating: Physics of the injection of particle acceleration at astrophysical heliospheric, and laboratory collisionless shocks, 2014.03, [URL]. |

124. | Thomson scattering measurement in laser experiment. |

125. | 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. |

126. | Relativistic Electron Acceleration in Low Mach Number Shocks. |

127. | Particle Acceleration in Colliding Two Oblique-Shocks. |

128. | Experimental and numerical studies on collisionless shocks. |

129. | Theoretical studies on the production of high Mach number collisionless shocks. |

130. | Yasuhiro Kuramitsu, Shuichi Matsukiyo, Spherical Shock in the presence of an External Magnetic Field, The Eighth International Conference on Inertial Fusion Sciences and Applications, 2013.09, [URL]. |

131. | Shuichi Matsukiyo, Yasuhiro Kuramitsu, KENTARO TOMITA, Thomson scattering in an unquiet plasma, The Eighth International Conference on Inertial Fusion Sciences and Applications, 2013.09, [URL]. |

132. | 中野谷賢, 松清 修一, Tohru Hada, Full Particle-In-Cell simulation of two colliding shocks, The 12th Asia Pacific Physics Conference, 2013.07, [URL]. |

133. | 松清 修一, PIC simulations of the termination shock, 8th European Workshop on Collisionless shocks, 2013.06, [URL]. |

134. | Electron acceleration at the termination shock, [URL]. |

135. | Numerical study on particle acceleration in multi-shock system, [URL]. |

136. | 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.. |

137. | 松清 修一, Manfred Scholer, Burst of reflected electrons in nonstationary quasi-perpendicular shocks, 2013 AGU Meeting of Americas, 2013.05, [URL], One-dimensional full particle-in-cell simulations are performed to investigate energetic electron bursts produced at a nonstationary quasi-perpendicular shock. Some of the incoming electrons are intermittently energized and reflected by interacting with nonstationary electromagnetic fields in the shock front. The reflected electrons form an upstream non-thermal population. The reflection process is strongly affected by the non-coplanar magnetic field which is temporarily rather strong in the transition region of a highly nonstationary shock. Oblique whistler waves in the shock transition region generated due to dispersion effect or due to modified two-stream instability may pitch angle scatter the electrons and thus blur the loss-cone feature of the reflected electrons. Some electrons are trapped by the waves while staying in the transition region and energized through the shock drift acceleration mechanism. They are suddenly released toward upstream when the magnetic overshoot begins to collapse in a reformation cycle resulting in the clumps of the reflected electrons in a phase space. It is also discussed how upstream physical quantities associated with the reflected electrons can give information about the shock front nonstationarity as well as about local small scale wave activities in the transition region.. |

138. | Full particle-in-cell simulations on the formation of electrostatic shock in a counter streaming plasma. |

139. | PIC simulation on the heliospheric termination shock. |

140. | Initial particle acceleration in collisionless shocks. |

141. | Experimental study on high Mach number collisionless shocks. |

142. | Particle acceleration at heliospheric termination shock. |

143. | Burst of reflected electrons in nonstationary shocks. |

144. | Multi-spacecraft observation of the non-stationary terrestrial bow shock. |

145. | Test particle simulation of diffusive shock acceleration process in a cosmic ray mediated shock. |

146. | PIC simulations on the heliospheric termination shock: Parameter survey. |

147. | S. Matsukiyo, M. Scholer, Microstructure of the Termination Shock: Full PIC Simulation, AOGS-AGU(WPGM) Joint Assembly, 2012.08, [URL], Microstructure of the termination shock reproduced by one-dimensional full particle-in-cell (PIC) simulations is investigated. 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. These features are due to the presence of pickup ions. Furthermore, when a relative pickup ion density is 30%, a shock is time stationary. For the case with low beta (=0.17) solar wind plasma, 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 beta gets five times higher (=0.85), on the other hand, the MTSI is weakened and the pre-heating of the solar wind plasma in the extended foot is suppressed. Other parameter dependence of detailed shock structure on relative pickup ion density, Alfven Mach number, ion-to-electron mass ratio, and electron plasma to cyclotron frequency ratio is discussed.. |

148. | Reformation at low-Mach-number perpendicular shocks, [URL]. |

149. | Structure of a termination shock: Parameter survey, [URL]. |

150. | Generation of high phase velocity waves and particle acceleration in a multi-ion-species plasma. |

151. | Generation of SPA waves in a multi-ion-species plasma. |

152. | Generation of SPA waves and particle acceleration in a multi-ion-species plasma. |

153. | Structure of heliospheric termination shock. |

154. | Full Particle-In-Cell Simulation on the Heliospheric Termination Shock, [URL]. |

155. | Generation of non-MHD waves and associated particle acceleration in a multi-ion-species plasma. |

156. | Particle acceleration through high phase velocity non-MHD waves in a multi-ion-species plasma. |

157. | Nonlinear excitation of high phase velocity non-MHD waves associated with solar flares. |

158. | Electron injection process due to shock wave drift acceleration. |

159. | Modified two-stream instability at perpendicular shocks:Full particle simulation. |

160. | Shuichi Matsukiyo, Manfred Scholer, Full Particle Simulation on Microstructure of Heliospheric Termination Shock, 2011 International Space Plasma Symposium (ISPS2011), 2011.08, [URL]. |

161. | Ion dynamics and microstructure of the heliospheric termination shock, [URL]. |

162. | Shuichi Matsukiyo, Full Particle-In-Cell Simulation on Collisionless Shocks:Electron and Ion Dynamics in the Transition Region, The 10th International School/Symposium for Space Simulations (ISSS-10), 2011.07, [URL]. |

163. | On the reformation at perpendicular shocks: full particle-in-cell simulations, [URL]. |

164. | Relativistic electron acceleration in a low Mach number shock, [URL]. |

165. | Microstructure of the heliospheric termination shock, [URL]. |

166. | On the reformation at perpendicular shock: 2D full PIC simulation, [URL]. |

167. | Relativistic shock drift acceleration in low Mach number shocks. |

168. | On the reformation at a quasi-perpendicular shock:Full particle-in-cell simulation. |

169. | Reflected Ions as a Remote Sensor of Nonstationary Shocks. |

170. | Behaviours of Nonthermal Electrons in Nonstationary Quasiperpendicular Shocks. |

171. | Electron acceleration in quasi-perpendicular shocks -- shock drift acc. revisited --, [URL]. |

172. | Kinetics of high energy electrons in nonstationary quasiperpendicular shocks, [URL]. |

173. | Mach number dependence of electron heating at high Mach number interplanetary shocks in the inner heliospere, [URL]. |

174. | Shuichi Matsukiyo, Manfred Scholer, Nonthermal electrons produced by supercritical quasi-perpendicular shocks, 2010 International Space Plasma Symposium, 2010.06, [URL]. |

175. | Electron acceleration in high beta quasi-perpendicular shocks. |

176. | Reflected electrons as remote sensor of dynamic behaviour of collisionless shocks. |

177. | Mach number dependence of electron heating in supercritical quasi-perpendicular shocks. |

178. | Mach number dependences of electron heating through microinstabilities in a shock transition region. |

179. | Shuichi Matsukiyo, Electron Heating through microinstabilities in High Mach Number Quasi-Perpendicular Shocks, 5th Korean Astrophysics Workshop on Shock Waves, Turbulence, and Particle Acceleration, 2009.11, [URL]. |

180. | Reflected Electrons Upstream of Collisionless Shocks. |

181. | Mach number dependence of electron heating in collisionless shocks. |

182. | Particle acceleration in developing relativistic Alfven turbulence. |

183. | Mach number dependences of electron heating efficiency in high Mach number shocks. |

184. | Efficiency of Electron Heating in High Mach Number Quasi-Perpendicular Shocks, [URL]. |

185. | Inter-scale coupling in a self-reformation process of quasi-perpendicular shocks. |

186. | Shuichi Matsukiyo, Manfred Scholer, Electron heating through microinstabilities in high Mach number quasi-perpendicular shocks, 8TH Annual International Astrophysics Conference, 2009.05, [URL]. |

187. | Electron heating in transition regions of high Mach number quasiperpendicular shocks. |

188. | Microphysics on shock reformation processes. |

189. | Production of backstreaming ions in oblique shocks: 1D PIC simulation. |

190. | Electrons' Behaviour in Quasi-Perpendicular Shocks. |

191. | Shock Self-Reformation Process Revisited: roles of small scale waves in the foot. |

192. | Details of self-reformation processes and micro-instabilities in quasi-perpendicular shocks. |

193. | Quasilinear analysis on electron heating in high Mach number shocks. |

194. | Shuichi Matsukiyo, Relativistic particle acceleration in developing Alfven turbulence, KINETIC MODELING OF ASTROPHYSICAL PLASMAS, 2008.10, [URL]. |

195. | Quasilinear analysis on electron heating in a foot of a high Mach number shock, [URL]. |

196. | Relativistic particle acceleration in developing Alfven turbulence, [URL]. |

197. | Perspective of researches on cosmic ray acceleration in collisionless shocks by utilizing the next-generation supercomputer. |

198. | Relativistic Particle Acceleration in Parametric Instabilities, [URL]. |

199. | Electron heating rate in a transition region of high Mach number shocks. |

200. | Shuichi Matsukiyo and Tohru Hada, Relativistic particle acceleration in coherent Alfven waves through parametric instabilities, International Workshop on Nonlinear Waves and Turbulence in Space Plasmas (NLW-7), 2008.04. |

201. | Shuichi Matsukiyo, Tohru Hada, Relativistic particle acceleration by coherent Alfven waves upstream of collisionless shocks, International Workshop on Plasma Shocks and Particle Acceleration, 2008.01. |

202. | Generation and nonlinear evolution of large amplitude upstream waves in an electron-positron shock wave and associated particle acceleration. |

203. | Instabilities in the Foot Region of Quasi-Perpendicular Shocks: Full Particle Electromagnetic Simulations, [URL]. |

204. | The Role of Modified Two-Stream Instability for Self-Reformation and Ion Acceleration in Quasi-Perpendicular Shocks, [URL]. |

205. | Shock reformation in unmagnetized plasmas. |

206. | Relativistic particle acceleration in large amplitude coherent Alfven waves, [URL]. |

207. | A 2-dimensional full particle simulation on parametric instabilities of large amplitude Alfven waves, [URL]. |

208. | Ring-beam instabilities driven by reflected electrons upstream of a quasi-perpendicular shock, [URL]. |

209. | A study of non-stationary shock front at a Q-perpendicular shock, [URL]. |

210. | Mechanisms of particle acceleration in relativistic plasmas, [URL]. |

211. | Shuichi Matsukiyo, Manfred Scholer, PIC simulations of quasi-perpendicular shocks: Roles of modified two-stream instability in particle heating, acceleration, and self-reformation processes, AOGS (Asia Oceania Geoscience Society) meeting 2007, 2007.08, [URL]. |

212. | A study of reformation at a Q-perpendicular shock: A Comparison of PIC simulation result with Cluster observation, [URL]. |

213. | Characteristics of quasi-perpendicular shocks accompanied by modified two-stream instability, [URL]. |

214. | Shuichi Matsukiyo, Manfred Scholer, Roles of Modified Two-Stream Instability in Supercritical Shock Waves, Japan-Korea Mini-Workshop 2007 on Laboratory, Space and Astrophysical Plasmas, 2007.04, [URL]. |

215. | Shuichi Matsukiyo, Manfred Scholer, Shock angle dependence of nonstationary behaviour of quasi-perpendicular shocks, 2007 IRCS Workshop on Shock Formation under Extreme Environments in the Universe, 2007.02. |

216. | Dissipation in high Mach number shocks: effects of microinstabilities. |

217. | Influences of microinstabilities on temporal and spatial scales of nonstationary behaviours in collisionless shock waves. |

218. | Physics of Inner Heliosphere and the MMO, [URL]. |

219. | Electron heating in the foot of high Mach number quasi-perpendicular shocks, [URL]. |

220. | Shuichi Matsukiyo and Manfred Scholer, Energy dissipation through microinstabilties in the foot of high Mach number quasi-perpendicular shocks, The Sixth International Workshop on Nonlinear Waves and Turbulence in Space Plasmas (NLW-6), 2006.10, [URL]. |

221. | Electron heating via multiple instabilities in the foot of a quasi-perpendicular shock, [URL]. |

222. | Nonlinear evolution of Alfven waves in a relativistic pair plasma. |

223. | Microinstabilities in a transition region of a quasi-perpendicular shock. |

224. | Numerical simulation of a plasma behaviour to time-varying external electromagnetic field, [URL]. |

225. | Microinstabilities generated in the foot of a high Mach number quasi-perpendicular shock, [URL]. |

226. | Cosmic ray acceleration and magnetic field amplification in the vicinity of a collisionless shock, [URL]. |

227. | Tutorial: Relativistic Plasmas and Particle Acceleration in Space and Laboratory - Recent Topics -, [URL]. |

228. | Shock waves in space plasmas: from theory/simulation to observation. |

229. | Nonlinear Alfven Waves in Relativistic Pair Plasma: Dispersion Relation. |

230. | Nonlinear Alfven Waves in Relativistic Pair Plasma: Full Particle Simulation. |

231. | 2D PIC simulation on microinstabilities in the foot of high Mach number quasi-perpendicular shocks. |

232. | Shuichi Matsukiyo, Manfred Scholer, Microinstabilities in collisionless shocks: recent simulation results, URSI (XXVIIIth General Assembly of International Union of Radio Science), 2005.10. |

233. | Long time evolution of a nonlinear Alfven wave in a strongly relativistic electron-positron plasma and associated partcle acceleration. |

234. | Numerical simulation on an electron-positron shock wave including a cosmic ray component. |

235. | Responses of a cylindrical plasma to external electromagnetic field: analytical theory and numerical simulation. |

236. | Numerical simulation of a plasma behavior to time-varying external electromagnetic field. |

237. | Parametric decays of nonlinear Alfven waves in an electron-positron plasma: kinetic theory and simulation results. |

238. | Finite amplitude Alfven wave in a strongly relativistic pair plasma: nonlinear dispersion relation. |

239. | Generation of whistler mode waves at the boundary of the lunar wake. |

240. | Numerical simulation of instabilities in transition regions of collisionless shocks. |

241. | Numerical simulation of plasma behavior under external electromagnetic field: possible applications to next generation electric propulsion systems. |

242. | Kinetic effects on the parametric decays of Alfven waves in relativistic paer plasmas. |

243. | Generation of MHD weves driven by high energy cosmic rays in the vicinity of shock waves. |

244. | Modified two-stream instability in a transition region of a supercritical quasi-perpendicular shock. |

245. | Modified two-stream instability in a high Mach number quasi-perpendicular shock front. |

246. | Long time evolution of nonlinear Alfven waves in a relativistic electron-positron plasma. |

247. | Modified two-stream instability at a high Mach number quasi-perpendicular shock front. |

248. | Structure of High Mach Number Quasi-Perpendicular Schoks and Wave-Particle Interactions in their Transition Region. |

249. | Interplanetary Shocks - past studies and unravelling sciences -. |

250. | Structure of high Mach number quasi-perpendicular collisionless shocks: mass ratio dependence. |

251. | Shuichi Matsukiyo, Manfred Scholer, Reformation of quasi-perpendicular shocks with realistic ion to electron mass ratio, COSPAR colloquia : Dynamical Processes in Critical Regions of the Heliosphere, 2004.03. |

252. | Generation of electron holes and electron heating in the auroral upward current (inverted V) region : A simulation study. |

253. | Quasi-perpendicular shocks : Full particle simulations with realistic ion to electron mass ratio. |

254. | High frequency waves and associated electron heating in the foot of quasi-perpendicular collisionless shocks. |

255. | Parametric instaiblities in a relativistic electron-positron plasma. |

256. | Metastable state of k=0 mode driven by relativistic ring distribution. |

257. | Long time evolution of electromagnetic waves driven by the relativistic ring distribution. |

258. | Jeans instability of a dusty plasma with neutral grains. |

259. | Jeans instability of a dusty plasma with neutral grains: Theoretical approach. |

260. | Long time evolution of electromagnetic waves driven by the relativistic ring distribution. |

261. | Comparison between the Landau and cyclotron resonances in the relativistic electron beam-plasma interactions. |

262. | Jeans instability in a dusty plasma: Hybrid simulation studies. |

263. | Parametric instabilities of finite amplitude electromagnetic waves in a relativistic electron-positron plasma. |

264. | Relativistic parametric instabilities of a finite amplitude Alfven wave. |

265. | Nonlinear long time evolution of electromagnetic waves driven by relativistic ring distribution. |

266. | Jeans instability in a dusty plasma : hybrid simulation. |

267. | Electromagnetic instability generated by relativistic ring distribution. |

268. | Jeans insatbility in a dusty plasma : linear dispersion relation. |

269. | Relativistic electron beam instability. |

270. | Generation and nonlinear evolution of k=0 mode in a plasma with relativistic ring distribution. |

Unauthorized reprint of the contents of this database is prohibited.