Morphology and Dynamics of Highly Supersonic Relativistic Jets

We present a simulation of a diffuse (η = 0.01), high-beam Mach number ( M b = 6.0), relativistic (beam Lorentz factor 22.4) axisymmetric jet, and we discuss its morphology and dynamics. The jet exhibits a prominent structure of oblique shocks inside the beam and possesses an extensive cocoon. This result is qualitatively different from the findings of other recent simulations of low-beam Mach number relativistic jets, where both features are absent. We find that the jet propagates very efficiently through the ambient medium. Its mean velocity is 15 times larger than that expected from classical (i.e., nonrelativistic) simulations. The simulations are performed with a high-resolution shock-capturing scheme using a Riemann solver which is based on the spectral decomposition of the Jacobian matrices of relativistic hydrodynamics.