Hydrodynamic free expansion of a localized relativistic plasma

A hydrodynamical treatment of the free expansion into vacuum by a relativistic plasma with an embedded magnetic field is presented. Both a linear and a spherical geometry are considered. For times when the system has expanded to sizes much larger than the initial size the energy density, number density, velocity, and magnetic field profiles are given. The general features of relativistic free expansion are discussed and compared with those of nonrelativistic free expansion