Localized nonlinear structures of intense electromagnetic waves in two-electron-temperature electron-positron-ion plasmas

Nonlinear propagation of intense electromagnetic waves in a hot electron-positron relativistic plasma containing a small fraction of cold electron-ion component has been investigated by deriving a generalized Schrodinger-Boussinesq system of coupled equations. The latter includes self-nonlinearity in the electromagnetic field amplitude due to the relativistic effects, and describes the coupling between the high-frequency electromagnetic wave and low-frequency electron-acoustic wave arising from the cold plasma component. For stationary propagation of finite amplitude waves, only supersonic solitons are found to exist, while for the quasineutral, linear low-frequency plasma response both sub- as well as supersonic solitons can occur. The relevance of these results to astrophysical situations is pointed out. (C) 1999 American Institute of Physics. [S1070-664X(99)00301-8].