NONLINEAR-ELECTRON-RESPONSE IMPACT ON THE EVOLUTION OF ION-ACOUSTIC-WAVE PACKETS IN A MAGNETIZED PLASMA

It has been argued by a number of authors that the development of inte rmittent, localized ion fluctuations in a two-species electron-ion dri fting ummagnetized plasma is possible. Compressive ion-acoustic solito ns can develop in such a plasma, but not rarefactive ones. In the case of a strongly magnetized two-component plasma where intermittent elec trostatic ion-acoustic and ion-cyclotron wave packets can be excited, we show that stationary shock solutions can exist. Their existence is due to the electron nonlinearity rather than the ion nonlinearity as i s the case when ion nonlinearities are included, as is often referred to as Korteweg-de Vries solitons. We also show that there is no statio nary solution when the Zakharov-Kuznetsov boundary conditions are impo sed. We analyze the stability of the shock solution and show that it i s possible to trigger a nonlinear instability in the case where a rare factive pulse is chosen as an initial condition. A nonlinear criterion for growth is developed.