The interaction of supernova blast waves with interstellar clouds using high-order adaptive mesh refinement methods

The interaction of a supernova shock with an interstellar cloud can be idealized to the problem of the interaction of a strong planar shock with a dense spherical inhomogeneity surrounded by a less dense fluid: the intercloud medium (ICM). This deceptively simple problem actually represents an extremely complex set of nonlinear hydrodynamic flows encompassing a rich set of shock/shock interaction phenomena. The authors have, for the first time, implemented local adaptive mesh refinement (AMR) techniques with second-order Godunov methods as developed recently by Berger and Colella to astrophysical gas dynamic scenarios to address this complex nonlinear problem. With AMR with a Godunov second-order method, they are able to evolve the hydrodynamics highly complex, multiply shock-distorted structures to a high degree of accuracy with a total of not more than 80,000 grid cells. A comparable calculation with a fixed grid would need >1,500,000 grid cells to achieve a similar accuracy. Clearly, adaptive mesh refinement techniques hold a major advantage in calculating complex compressible gas dynamic flows one to two orders of magnitude more rapidly than standard techniques