Magnetic ramp scale at supercritical perpendicular collisionless shocks: Full particle electromagnetic simulations

Journal Article · Sun Sep 15 04:00:00 EDT 2013 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4821825· OSTI ID:22220583

Yang, Zhongwei ^[1]; Lu, Quanming; Gao, Xinliang; Huang, Can ^[2]; Yang, Huigen; Hu, Hongqiao; Han, Desheng ^[3]; Liu, Ying ^[1]

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1. State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100080 (China)
2. CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei 230026 (China)
3. SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, 200136 (China)

Supercritical perpendicular collisionless shocks are known to exhibit foot, ramp, and overshoot structures. The shock ramp structure is in a smaller scale in contrast to other microstructures (foot and overshoot) within the shock front. One-dimensional full particle simulations of strictly perpendicular shocks over wide ranges of ion beta β{sub i}, Alfvén Mach number M{sub A}, and ion-to-electron mass ratio m{sub i}/m{sub e} are presented to investigate the impact of plasma parameters on the shock ramp scale. Main results are (1) the ramp scale can be as small as several electron inertial length. (2) The simulations suggest that in a regime below the critical ion beta value, the shock front undergoes a periodic self-reformation and the shock ramp scale is time-varying. At higher ion beta values, the shock front self-reformation is smeared. At still higher ion beta value, the motion of reflected ions is quite diffuse so that they can lead to a quasi-steady shock ramp. Throughout the above three conditions, the shock ramp thickness increases with β{sub i}. (3) The increase (decrease) in Mach number and the decrease (increase) in the beta value have almost equivalent impact on the state (i.e., stationary or nonstationary) of the shock ramp. Both of front and ramp thicknesses are increased with M{sub A}.

• OSTI ID: 22220583
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 9 Vol. 20; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALFVEN WAVES
ELECTRONS
IONS
LENGTH
MACH NUMBER
MASS
MICROSTRUCTURE
ONE-DIMENSIONAL CALCULATIONS
PARTICLES
PERIODICITY
PLASMA
PLASMA SIMULATION
SHOCK WAVES
SOCIO-ECONOMIC FACTORS
THICKNESS