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Title: Very High Mach-Number Electrostatic Shocks in Collisionless Plasmas

Abstract

The kinetic theory of collisionless electrostatic shocks resulting from the collision of plasma slabs with different temperatures and densities is presented. The theoretical results are confirmed by self-consistent particle-in-cell simulations, revealing the formation and stable propagation of electrostatic shocks with very high Mach numbers (M>>10), well above the predictions of the classical theories for electrostatic shocks.

Authors:
; ; ;  [1]
  1. GoLP/Centro de Fisica dos Plasmas, Instituto Superior Tecnico, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal)
Publication Date:
OSTI Identifier:
20777012
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevLett.96.045005; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COLLISIONLESS PLASMA; MACH NUMBER; PLASMA DENSITY; PLASMA SIMULATION; SHOCK WAVES

Citation Formats

Sorasio, G., Marti, M., Fonseca, R., and Silva, L.O.. Very High Mach-Number Electrostatic Shocks in Collisionless Plasmas. United States: N. p., 2006. Web. doi:10.1103/PhysRevLett.96.045005.
Sorasio, G., Marti, M., Fonseca, R., & Silva, L.O.. Very High Mach-Number Electrostatic Shocks in Collisionless Plasmas. United States. doi:10.1103/PhysRevLett.96.045005.
Sorasio, G., Marti, M., Fonseca, R., and Silva, L.O.. Fri . "Very High Mach-Number Electrostatic Shocks in Collisionless Plasmas". United States. doi:10.1103/PhysRevLett.96.045005.
@article{osti_20777012,
title = {Very High Mach-Number Electrostatic Shocks in Collisionless Plasmas},
author = {Sorasio, G. and Marti, M. and Fonseca, R. and Silva, L.O.},
abstractNote = {The kinetic theory of collisionless electrostatic shocks resulting from the collision of plasma slabs with different temperatures and densities is presented. The theoretical results are confirmed by self-consistent particle-in-cell simulations, revealing the formation and stable propagation of electrostatic shocks with very high Mach numbers (M>>10), well above the predictions of the classical theories for electrostatic shocks.},
doi = {10.1103/PhysRevLett.96.045005},
journal = {Physical Review Letters},
number = 4,
volume = 96,
place = {United States},
year = {Fri Feb 03 00:00:00 EST 2006},
month = {Fri Feb 03 00:00:00 EST 2006}
}
  • A problem of critical importance to space physics and astrophysics is the existence and properties of high--Mach-number shocks. In this Letter we present the preliminary results of a simulation of a perpendicular shock with Alfven Mach number 22. We show that for sufficiently small electron resistivity the dissipation for this shock is provided by a periodic, rather than time-stationary, reflection of ions. We discuss the problem of electron heating and the extension to higher Mach numbers.
  • Astrophysical shocks, such as planetary bow shocks or supernova remnant shocks, are often in the high or very-high Mach number regime, and the structure of such shocks is crucial for understanding particle acceleration and plasma heating, as well inherently interesting. Recent magnetic field observations at Saturn’s bow shock, for Alfvén Mach numbers greater than about 25, have provided evidence for periodic non-stationarity, although the details of the ion- and electron-scale processes remain unclear due to limited plasma data. High-resolution, multi-spacecraft data are available for the terrestrial bow shock, but here the very high Mach number regime is only attained onmore » extremely rare occasions. Here we present magnetic field and particle data from three such quasi-perpendicular shock crossings observed by the four-spacecraft Cluster mission. Although both ion reflection and the shock profile are modulated at the upstream ion gyroperiod timescale, the dominant wave growth in the foot takes place at sub-proton length scales and is consistent with being driven by the ion Weibel instability. The observed large-scale behavior depends strongly on cross-scale coupling between ion and electron processes, with ion reflection never fully suppressed, and this suggests a model of the shock dynamics that is in conflict with previous models of non-stationarity. Thus, the observations offer insight into the conditions prevalent in many inaccessible astrophysical environments, and provide important constraints for acceleration processes at such shocks.« less