Formation, Evolution, and the Structure of Fronts Produced By Unsteady Injection of Highly Magnetized, Relativistic Flows

We study the formation, evolution and structure of dissipative fronts produced by overtaking collisions of relativistic streams, with emphasis on strongly magnetized flows. The evolution of the system is followed using analytical approach in the simple wave regime and numerical simulations in the non-simple wave regime, until a steady-state is reached. The steady-state structure of the front is then examined by solving the appropriate jump conditions. The conversion of magnetic energy into kinetic energy is parametrized in terms of the Alfvén 4-velocity inside the front. The implications for gammaray jets are briefly discussed.