On the interactions of Riemann waves in relativistic magnetohydrodynamics

The existence of certain classes of solutions of the fundamental system of equations of relativistic MHD is studied, continuing the analysis of Malyszko (1986) from a domain of relativistic gasdynamics. The generalized Riemann invariants method is applied, making it possible to construct solutions of the Riemann-wave type of nonlinear, nonelliptic systems of partial differential equations. Isentropic flows of a perfect compressible fluid of infinite conductivity in an EM field with induction are considered, and it is shown that there exists a local frame of reference, in which Alfven flows are stationary and satisfy a simpler system of equations than the starting one.