Adiabatic self-similar blast waves, their radial instabilities, and their application to supernova remnants

Abstract

It is shown that adiabatic self-similar motion resulting from a strong spherical explosion in a medium with density rho/sub 0/=Ar/sup -omega/is unstable to radial perturbations of arbitrary amplitude when ..omega.. ..omega../sub +/, or ..omega.. (5..gamma..-4)/..gamma.., instability has not been proved or disproved. This result indicates that physical systems subject to these instabilities do not evolve to the self-similar state from the initial chaotic explosion. It is also shown that many self-similar systems violate the adiabatic and single-fluid assumptions which are made in deriving the motion. The usual model taken to apply to the evolution of supernova remnants (..omega..=0, ..gamma..=5/3) is unstable and violates both the adiabatic and one-fluid assumptions. Thus, supernova remnants cannot be evolving in an adiabatic self-similar manner, though further quantitative analysis is needed to determine the magnitude of the deviations.