Transverse quasilinear relaxation in inhomogeneous magnetic field

Abstract

Transverse quasilinear relaxation of the cyclotron-Cherenkov instability in the inhomogeneous magnetic field of pulsar magnetospheres is considered. We find quasilinear states in which the kinetic cyclotron-Cherenkov instability of a beam propagating through strongly magnetized pair plasma is saturated by the force arising in the inhomogeneous field due to the conservation of the adiabatic invariant. The resulting wave intensities generally have nonpower law frequency dependence, but in a broad frequency range can be well approximated by the power law with the spectral index -2. The emergent spectra and fluxes are consistent with the one observed from pulsars.