Glimm-Godunov's method for cosmic-ray-hydrodynamics

JOURNAL OF COMPUTATIONAL PHYSICS

卷:227

Article

Miniati, Francesco

关键词: hydrodynamics;    cosmic-rays;    numerical methods;    Godunov's method;    Glimm's methods;   

DOI  :  10.1016/j.jcp.2007.08.013

来源: Elsevier

【 摘 要 】

A numerical method for integrating the equations describing a dynamically coupled system made of a fluid and cosmic-rays is developed. In smooth flows the effect of CR pressure is accounted for by modification of the characteristic equations and the energy exchange between cosmic-rays and the fluid, due to diffusive processes in configuration and momentum space, is modeled with a flux conserving method. Provided the shock acceleration efficiency as a function of the upstream conditions and shock Mach number, we show that the Riemann solver can be modified to take into account the cosmic-ray mediation without having to resolve the cosmic-ray induced substructure. Shocks are advanced with Glimm's method which preserves their discontinuous character without any smearing, thus allowing to maintain self-consistency in the shock solutions. In smooth flows either Glimm's or a higher order Godunov's method can be applied, with the latter producing better results when approximations are introduced in the Riemann solver. (c) 2007 Elsevier Inc. All rights reserved.

【 授权许可】

Free