Two-dimensional Numerical Study for Rayleigh-Taylor and Richtmyer-Meshkov Instabilities in Relativistic Jets

We study the stability of a non-rotating single-component jet using two-dimensional special relativistic hydrodynamic simulations. By assuming translational invariance along the jet axis, we exclude the destabilization effect by Kelvin-Helmholtz mode. The nonlinear evolution of the transverse structure of the jet with a normal jet velocity is highlighted. An intriguing finding in our study is that Rayleigh-Taylor and Richtmeier-Meshkov type instabilities can destroy cylindrical jet configuration as a result of spontaneously induced radial oscillating motion. This is powered by in-situ energy conversion between the thermal and bulk kinetic energies. The effective inertia ratio of the jet to the surrounding medium $\eta$ determines a threshold for the onset of instabilities. The condition $\eta < 1$ should be satisfied for the transverse structure of the jet being persisted.