Synthetic Observation of Turbulent Supernova Remnants

Abstract

It is known that observations of polarized radio synchrotron emissions from young supernova remnants show radially oriented distributions of magnetic field. By using synthetic polarization observations of the results of three-dimensional magnetohydrodynamics simulations, we find that the radially oriented distribution of magnetic field can be reproduced by turbulent dynamo mechanism induced by the Richtmyer-Meshkov instability. In the simulation, we consider propagation of a supernova blast wave shock in realistic inhomogeneous interstellar medium. Interaction between the density inhomogeneity and the shock wave induces the so-called Richtmyer-Meshkov instability that generates shear of radial-component velocity in the downstream of the blast wave. In such medium, magnetic field lines are stretched by the shear motion that leads to amplification of radial-component magnetic field. Thus, the downstream magnetic field is oriented parallel to the shock normal. We conclude that the observed polarized synchrotron emission is successfully explained by the dynamo effect induced by the Richtmyer-Meshkov instability.