Kinetic inhibition of MHD-shocks in the vicinity of a parallel magnetic field

Abstract

According to magnetohydrodynamics (MHD), the encounter of two collisional magnetized plasmas at high velocity gives rise to shock waves. Investigations conducted so far have found that the same conclusion still holds in the case of collisionless plasmas. For the case of a flow-aligned field, MHD stipulates that the field and the fluid are disconnected, so that the shock produced is independent of the field. We present a violation of this MHD prediction when considering the encounter of two cold pair plasmas along a flow-aligned magnetic field. As the guiding magnetic field grows, isotropization is progressively suppressed, resulting in a strong influence of the field on the resulting structure. A micro-physics analysis allows to understand the mechanisms at work. Particle-in-cell simulations also support our conclusions and show that the results are not restricted to a strictly parallel field.

To appear in Journal of Plasma Physics

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Cited by in corpus (7)

• Long-term Evolution of Relativistic Unmagnetized Collisionless Shocks
• Density jump as a function of magnetic field strength for parallel collisionless shocks in pair plasmas
• Density jump as a function of magnetic field for collisionless shocks in pair plasmas: the perpendicular case
• Constraining Magnetization of Gamma-Ray Bursts Outflows using Prompt Emission Fluence
• Modified jump conditions for parallel collisionless shocks
• Particle trajectories in Weibel filaments: influence of external field obliquity and chaos
• Kinetic Simulations of Strongly-Magnetized Parallel Shocks: Deviations from MHD Jump Conditions