On the evolution of a nonlinear Alfven pulse

The temporal evolution of weakly nonlinear, plane. linear ly polarized Alfv en pulses in a cold homogeneous plasma is investigated. A static initial pu lse-like disturbance in transverse velocity produces two Alfven pulses that travel in opposite directions along the magnetic field. The ponderomotive force of the two pulses produces a static shock in longitudinal velocity? a t the starting position The travelling: pulses form a shock front that is g overned by the scalar Cohen-Kulsrud equation. We find good agreement betwee n the analytical solutions we derive and the results: from a fully nonlinea r numerical MHD code.