Modified Clemmow-Mullaly-Allis diagram for large-amplitude electromagnetic waves in magnetoplasmas

A possible modification to the well known Clemmow-Mullaly-Allis diagram is analyzed by taking into account the ponderomotive force due to a large-amplitude electromagnetic field in magnetoplasmas. We restrict our attention here to the propagations parallel (the right- and left-hand circularly polarized waves) and/or perpendicular (the ordinary and extraordinary modes) to the static magnetic field. Simple expressions are obtained for the cut-off conditions of the waves except for the extraordinary mode. In the latter case, the cut-off condition is calculated numerically by solving an integral equation. The cut-off lines are shown to move towards the higher densities with increasing wave amplitude. (auth.)