Non-linear Coupling between Electromagnetic and Sound Waves in Relativistically Hot Electron-Positron Magnetoplasmas

The non-linear interaction between circularly polarized electromagnetic and sound waves in relativistically hot electron-positron magnetoplasmas is considered. The ponderomotive-force and relativistic-mass-variation non-linearities are incorporated. The modulational instability and the envelope soliton formation are studied. The present investigation should be useful for understanding non-linear wave motions in astrophysical plasmas.