Synthetic Observation of Turbulent Supernova Remnants

Abstract

It is known that observations of polarized radio synchrotron emissions from young supernova remnants (SNRs) suggest radially oriented distributions of magnetic field. In this poster, by using synthetic polarization observations of the results of three-dimensional magnetohydrodynamics (MHD) simulations, we show that the radially oriented distribution of magnetic field can be reproduced by turbulent dynamo mechanism induced by the Richtmyer-Meshkov instability. Figure 1 shows the result of synthetic observation of polarized radio synchrotron emissions from the simulated SNR. In the simulation, we consider propagation of a supernova blast wave shock in realistic inhomogeneous interstellar medium. Interactions between the density inhomogeneity and the shock wave induce the so-called Richtmyer-Meshkov instability that generates shear of x-component velocity in the downstream of the blast wave. In such medium, magnetic field lines frozen-in the fluid are stretched by the shear motion that leads to amplification of x-component magnetic field. Thus, the downstream magnetic field is oriented parallel to the shock normal (x-direction). We conclude that the observed polarized synchrotron emission can be explained by dynamo effect induced by anisotropic velocity shear (or anisotropic turbulence) driven by the Richtmyer-Meshkov instability.