TRANSIENT EVOLUTION OF LOCALIZED ION-ACOUSTIC-WAVES IN PLASMAS

We derive an integrable model of coupled equations for the description of the transient evolution of small-amplitude ion acoustic waves interacting with the electromagnetic waves. We obtain then a universal behavior of the acoustic wave driven by a strong ponderomotive force: The asymptotic solution consists of two supersonic localized singular coherent structures following a sonic wave front and asymptotically colliding at the sound speed. The reflected electromagnetic wave presents singularities in the same regions as the acoustic wave.