Understanding Streaming Instabilities in the Limit of High Cosmic Ray Current Density

2024/11/08 by Lichko, Emily, Caprioli, Damiano, Schroer, Benedikt +1 · 3 citations
#FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Plasma Physics (physics.plasm-ph)

paper · doi:10.48550/arxiv.2411.05704

Abstract

A critical component of particle acceleration in astrophysical shocks is the non-resonant (Bell) instability, where the streaming of cosmic rays (CRs) leads to the amplification of magnetic fields necessary to scatter particles. In this work we use kinetic particle-in-cells simulations to investigate the high-CR current regime, where the typical assumptions underlying the Bell instability break down. Despite being more strongly driven, significantly less magnetic field amplification is observed compared to low-current cases, an effect due to the anisotropic heating that occurs in this regime. We also find that electron-scale modes, despite being fastest growing, mostly lead to moderate electron heating and do not affect the late evolution or saturation of the instability.

Cited by

• Magnetic Field Amplification and Particle Acceleration in Weakly Magnetized Trans-relativistic Electron-ion Shocks
• Impact of Cosmic Ray Distribution on the Growth and Saturation of Bell Instability
• Speed-dependent Threshold for Electron Injection into Diffusive Shock Acceleration

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