### Abstract

Large-scale two-dimensional (2D) full particle-in-cell (PIC) simulations are carried out for studying the relationship between the dynamics of a perpendicular shock and microinstabilities generated at the shock foot. The structure and dynamics of collisionless shocks are generally determined by Alfven Mach number and plasma beta, while microinstabilities at the shock foot are controlled by the ratio of the upstream bulk velocity to the electron thermal velocity and the ratio of the plasma-to-cyclotron frequency. With a fixed Alfven Mach number and plasma beta, the ratio of the upstream bulk velocity to the electron thermal velocity is given as a function of the ion-to-electron mass ratio. The present 2D full PIC simulations with a relatively low Alfven Mach number (M_{A} ∼ 6) show that the modified two-stream instability is dominant with higher ion-to-electron mass ratios. It is also confirmed that waves propagating downstream are more enhanced at the shock foot near the shock ramp as the mass ratio becomes higher. The result suggests that these waves play a role in the modification of the dynamics of collisionless shocks through the interaction with shock front ripples.

Original language | English |
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Article number | 022102 |

Journal | Physics of Plasmas |

Volume | 21 |

Issue number | 2 |

DOIs | |

Publication status | Published - Feb 1 2014 |

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### All Science Journal Classification (ASJC) codes

- Condensed Matter Physics

### Cite this

*Physics of Plasmas*,

*21*(2), [022102]. https://doi.org/10.1063/1.4863836

**Dynamics and microinstabilities at perpendicular collisionless shock : A comparison of large-scale two-dimensional full particle simulations with different ion to electron mass ratio.** / Umeda, Takayuki; Kidani, Yoshitaka; Matsukiyo, Shuichi; Yamazaki, Ryo.

Research output: Contribution to journal › Article

*Physics of Plasmas*, vol. 21, no. 2, 022102. https://doi.org/10.1063/1.4863836

}

TY - JOUR

T1 - Dynamics and microinstabilities at perpendicular collisionless shock

T2 - A comparison of large-scale two-dimensional full particle simulations with different ion to electron mass ratio

AU - Umeda, Takayuki

AU - Kidani, Yoshitaka

AU - Matsukiyo, Shuichi

AU - Yamazaki, Ryo

PY - 2014/2/1

Y1 - 2014/2/1

N2 - Large-scale two-dimensional (2D) full particle-in-cell (PIC) simulations are carried out for studying the relationship between the dynamics of a perpendicular shock and microinstabilities generated at the shock foot. The structure and dynamics of collisionless shocks are generally determined by Alfven Mach number and plasma beta, while microinstabilities at the shock foot are controlled by the ratio of the upstream bulk velocity to the electron thermal velocity and the ratio of the plasma-to-cyclotron frequency. With a fixed Alfven Mach number and plasma beta, the ratio of the upstream bulk velocity to the electron thermal velocity is given as a function of the ion-to-electron mass ratio. The present 2D full PIC simulations with a relatively low Alfven Mach number (MA ∼ 6) show that the modified two-stream instability is dominant with higher ion-to-electron mass ratios. It is also confirmed that waves propagating downstream are more enhanced at the shock foot near the shock ramp as the mass ratio becomes higher. The result suggests that these waves play a role in the modification of the dynamics of collisionless shocks through the interaction with shock front ripples.

AB - Large-scale two-dimensional (2D) full particle-in-cell (PIC) simulations are carried out for studying the relationship between the dynamics of a perpendicular shock and microinstabilities generated at the shock foot. The structure and dynamics of collisionless shocks are generally determined by Alfven Mach number and plasma beta, while microinstabilities at the shock foot are controlled by the ratio of the upstream bulk velocity to the electron thermal velocity and the ratio of the plasma-to-cyclotron frequency. With a fixed Alfven Mach number and plasma beta, the ratio of the upstream bulk velocity to the electron thermal velocity is given as a function of the ion-to-electron mass ratio. The present 2D full PIC simulations with a relatively low Alfven Mach number (MA ∼ 6) show that the modified two-stream instability is dominant with higher ion-to-electron mass ratios. It is also confirmed that waves propagating downstream are more enhanced at the shock foot near the shock ramp as the mass ratio becomes higher. The result suggests that these waves play a role in the modification of the dynamics of collisionless shocks through the interaction with shock front ripples.

UR - http://www.scopus.com/inward/record.url?scp=84894478411&partnerID=8YFLogxK

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U2 - 10.1063/1.4863836

DO - 10.1063/1.4863836

M3 - Article

AN - SCOPUS:84894478411

VL - 21

JO - Physics of Plasmas

JF - Physics of Plasmas

SN - 1070-664X

IS - 2

M1 - 022102

ER -