Time Evolution of Cosmic‐Ray Modified Plane Shocks

We have developed a novel computer code designed to follow the evolution ofcosmic-ray modified shocks, including the full momentum dependence of theparticles for a realistic diffusion coefficient model. In this form the problemis technically very difficult, because one needs to cover a wide range ofdiffusive scales, beginning with those slightly larger than the physical shockthickness. With most finite difference schemes for Euler's equations thenumerical shock thickness is at least one zone across, so this provides a lowerbound on the physical scale for diffusive transport computation. Our code usessub-zone shock tracking and multi-level adaptive mesh refinement to provideenhanced spatial resolution around shocks at modest cost compared to the coarsegrid and vastly improved cost effectiveness compared to a uniform, highlyrefined grid. We present and discuss the implications from our initial results.Comment: 7 pages, 11 figures, accepted by Ap