Time-dependent simulation of cosmic-ray shocks, including Alfven transport

Abstract

view Abstract Citations (8) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Time-dependent Simulation of Cosmic-Ray Shocks, Including Alfven Transport Jones, T. W. Abstract Time evolution of plane, cosmic-ray modified shocks has been simulated numerically for the case with parallel magnetic fields. Computations were done in a 'three-fluid' dynamical model incorporating cosmic-ray and Alfven-wave energy transport equations. Nonlinear feedback from the cosmic rays and Alfven waves is included in the equation of motion for the underlying plasma, as is the finite propagation speed and energy dissipation of the Alfven waves. Exploratory results confirm earlier, steady state analyses that found these Alfven transport effects to be potentially important when the upstream Alfven speed and gas sound speeds are comparable. As noted earlier, Alfven transport effects tend to reduce the transfer of energy through a shock from gas to energetic particles. These studies show as well that the timescale for modification of the shock is altered in nonlinear ways. It is clear, however, that the consequences of Alfven transport are strongly model dependent and that both advection of cosmic rays by the waves and dissipation of wave energy in the plasma will be important to model correctly when quantitative results are needed. Comparison is made between simulations based on a constant diffusion coefficient and more realistic diffusion models allowing the diffusion coefficient to vary in response to changes in Alfven wave intensity. No really substantive differences were found between them. Publication: The Astrophysical Journal Supplement Series Pub Date: February 1994 DOI: 10.1086/191934 Bibcode: 1994ApJS...90..969J Keywords: Computerized Simulation; Cosmic Rays; Energy Transfer; Magnetohydrodynamic Waves; Shock Wave Propagation; Time Dependence; Beta Particles; Energy Dissipation; Equations Of Motion; Flux Density; Gas Dynamics; Magnetic Fields; Three Dimensional Flow; Wave-Particle Interactions; Astrophysics; ISM: COSMIC RAYS; MAGNETOHYDRODYNAMICS: MHD; SHOCK WAVES full text sources ADS |