Saturated magnetic field amplification at supernova shocks

Abstract

Cosmic-ray streaming instabilities at supernova shocks are discussed in the quasilinear diffusion formalism which takes into account the feedback effect of wave growth on the cosmic ray streaming motion. In particular, the nonresonant instability that leads to magnetic field amplification in the short wavelength regime is considered. The linear growth rate is calculated using kinetic theory for a streaming distribution. We show that the nonresonant instability is actually driven by a compensating current in the background plasma. The nonresonant instability can develop into a nonlinear regime generating turbulence. The saturation of the amplified magnetic fields due to particle diffusion in the turbulence is derived analytically. It is shown that the evolution of parallel and perpendicular cosmic-ray pressures is predominantly determined by nonresonant diffusion. However, the saturation is determined by resonant diffusion which tends to reduce the streaming motion through pitch angle scattering. The saturated level can exceed the mean background magnetic field.

8 pages. Accepted for publication in MNRAS

References in corpus (6)

• A kinetic approach to cosmic ray induced streaming instability at supernova shocks
• Study of Nonthermal Emission from SNR RX J1713.7-3946 with Suzaku
• Production of Magnetic Turbulence by Cosmic Rays Drifting Upstream of Supernova Remnant Shocks
• Modeling Bell's Non-resonant Cosmic Ray Instability
• A current driven instability in parallel, relativistic shocks
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Cited by in corpus (16)

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• Environments for Magnetic Field Amplification by Cosmic Rays
• Magnetic fields in cosmic particle acceleration sources
• Acceleration of cosmic rays by young core-collapse supernova remnants
• Time-dependent particle acceleration in supernova remnants in different environments
• The nonlinear saturation of the non-resonant kinetically driven streaming instability
• Kinetic simulations of turbulent magnetic-field growth by streaming cosmic rays
• Reacceleration of electrons in supernova remnants
• Electron Heating, Magnetic Field Amplification, and Cosmic Ray Precursor Length at Supernova Remnant Shocks
• Spatio-temporal evolution of the nonresonant instability in shock precursors of young supernova remnants
• Could Cosmic Rays Affect Instabilities in the Transition Layer of Nonrelativistic Collisionless Shocks?
• Magnetic and density spikes in cosmic ray shock precursors
• Cosmic-ray current-driven instabilities -- revisiting environmental conditions
• Time-dependent treatment of cosmic-ray spectral steepening due to turbulence driving