Unified kinetic theory of induced scattering: Compton, Brillouin, and Raman processes in magnetized electron and positron pair plasma

Abstract: We present a unified theoretical framework for induced (stimulated) scattering-parametric instabilities of electromagnetic waves, including induced Compton, stimulated Brillouin, and stimulated Raman scattering (SRS) in strongly magnetized electron-positron pair plasma. By solving the dispersion relations derived from kinetic theory, taking into account the ponderomotive force due to the beat of incident and scattered waves, we obtain analytical expressions for the linear growth rates of the ordinary, neutral, and charged modes of density fluctuations. Our results clarify which type of scattering dominates under different thermal coupling, resonance, and density conditions. In strong magnetic fields, scattering of perpendicularly polarized waves is generally suppressed, but by different powers of the cyclotron frequency. Moreover, SRS, which is forbidden in unmagnetized electron and positron pair plasma, becomes possible in the charged mode. This framework enables a comprehensive evaluation of induced scattering in extreme astrophysical and laboratory plasma, such as fast radio burst (FRB) emission and propagation in magnetar magnetospheres.