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

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 ofmore » front and ramp thicknesses are increased with M{sub A}.« less
Authors:
 [1] ;  [2] ; ; ;  [3] ; ; ;  [4] ;  [1]
  1. State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100080 (China)
  2. (China)
  3. CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei 230026 (China)
  4. SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, 200136 (China)
Publication Date:
OSTI Identifier:
22220583
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 9; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
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