On the stability of nonlinear magneto-sonic waves in a collisionless plasma

The stability of a magneto-sonic wave of small (but finite) amplitude, propagating in a low- β plasma across a magnetic field, is investigated. It is shown that such a wave is unstable with respect to parametric splitting into many satellite waves. Wavenumbers of the satellite waves differ from that of the original magneto-sonic wave. Thus, the sateffite waves leave an interaction space, and form oscillating ‘tails ’ in front of and behind the initial pulse.