THE SMALL AMPLITUDE MAGNETOHYDRODYNAMIC RIEMANN PROBLEM

The small amplitude magnetohydrodynamic Riemann problem is studied usi ng the Cohen-Kulsrud-Burgers equations. Unlike the coplanar Riemann pr oblem, the evolution of noncoplanar Riemann problems is not self-simil ar and its flow structures could change in time. But its large-time be havior is very simple and a time-dependent 2-->3 intermediate shock is always involved for the noncoplanar field rotations. The time-depende nt 2-->3 intermediate shock has a well-defined structure and exists fo r any degree of field rotation.