NEAR-MAGNETOSONIC ENVELOPE UPPER-HYBRID WAVES.

A systematic analysis of envelope upper-hybrid wave propagation near the magnetosonic speed has been presented. Using the full set of fluid equations for the low-frequency dynamics, we obtain various model nonlinear equations describing the magnetosonic response to the envelope waves. In particular, we derive driven KdV as well as driven Boussinesq equations that are valid for near-magnetosonic propagation. Exact stationary solutions of the coupled equations are explicitly obtained. It is shown that a new class of upper-hybrid solitons with antisymmetric wave envelope exist for near-magnetosonic propagation. Integral invariants for the driven KdV case have been obtained and evaluated for localized solutions. A set of stationary governing equations is derived that takes account of the full nonlinearity in the low-frequency response as well as departures from the frozen-in-field approximation. A detailed comparison of the various model equations as well as their validity has been made.