Regimes of the Vishniac–Ryu Decelerating Shock Instability

摘要

Here we revisit the derivation of the instability of dense shocked layers, originally developed by Vishniac and Ryu. Our motivation is that density profiles found in actual astrophysical and laboratory systems often do not match the assumptions in that paper. In order to identify the anticipated theoretical growth rates for various circumstances, one must first revisit the derivation and allow for the possibility that the density scale length differs, in magnitude and/or in sign, from the isothermal scale height. This analysis leads us to find regimes of purely convective instability and also of Vishniac stabilization of this instability, in addition to some new regimes of Vishniac behavior. We also identify a typographical error in the original paper that matters for quantitative evaluation of growth rates.