Rayleigh-Taylor and Richtmyer-Meshkov Instabilities in Relativistic Hydrodynamic Jets

We investigate the stability of relativistic jets using three-dimensional hydrodynamic simulations. The propagation of relativistic flow that is continuously injected from the boundary of computational domain into a uniform ambient medium is solved. An intriguing finding in our study is that Rayleigh-Taylor and Richtmyer-Meshkov type instabilities grow at the interface between the jet and surrounding medium as a result of spontaneously induced radial oscillating motion. It is powered by in situ energy conversion between the thermal and bulk kinetic energies of the jet. From complementary two-dimensional simulations of transverse structure of the jet, we find the effective inertia ratio of the jet to the surrounding medium determines a threshold for the onset of instabilities. The mixing between light faster jet and slow heavier external matters due to these instabilities causes the deceleration of the jet