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.