Magnetohydrodynamic waves in a homogeneous plasma convected uniformly at relativistic speed

The plasma in several physical situations such as movement of electrons along the geomagnetic field lines in the magnetosphere, the movement of the ionosphere, propagation of cosmic rays, etc., can be appropriately simulated by a drifting relativistic model. Keeping this in view, a general dispersion relation for magnetohydrodynamic (MHD) waves has been derived in a laboratory stationary coordinate system with respect to which plasma is drifting with a velocity which need not be small compared with the speed of light. This dispersion relation gives several earlier well-known results for MHD waves supported by an ideal relativistic plasma. The characteristic equation for arbitrary direction of propagation with reference to the ambient magnetic field is quite unwieldy. So, the detailed discussion is confined to the special cases when the propagation vector is along or across the magnetic field. However, wherever feasible, approximate solutions for arbitrary direction of propagation have also been discussed. (C) 2000 American Institute of Physics. [S1070-664X(00)04809-6].