Nonlinear propagation of inertial Alfven waves in auroral plasmas

The nonlinear interaction between large amplitude dispersive inertial Alfve n waves (DIAWs) and electrostatic density perturbations is considered. For this purpose, a pair of coupled equations is derived, accounting for the po nderomotive force driven density perturbations. The modulational instabilit y of a constant amplitude DIAWs is studied, and the possibility of DIAW ind uced quasistationary (supersonic) density channels (cavities) is pointed ou t. Specifically, it is found that ponderomotive force driven density caviti es cannot be formed within the quasistationary model. The relevance of our investigation to the nonlinear structures and the ion energization in space and laboratory plasmas is discussed. (C) 1999 American Institute of Physic s. [S1070-664X(99)03205-X].