Cherenkov-Curvature Radiation and Pulsar Radio Emission Generation

Abstract

Electromagnetic processes associated with a charged particle moving in a strong circular magnetic field are considered in cylindrical coordinates. We investigate the relation between the vacuum curvature emission and Cherenkov emission and argue that, for the superluminal motion of a particle in the inhomogeneous magnetic field in a dielectric, the combined effects of magnetic field inhomogeneity and the presence of a medium give rise to the synergetic Cherenkov-curvature emission process. We find the conditions under which the operator relations between electric field and electric displacement in cylindrical coordinates may be approximated by algebraic relations. For nonresonant electromagnetic waves, the interaction with particles streaming along the curved magnetic field may be described in the WKB approximation. For resonant waves interacting with superluminal particles we use a plane-wave approximation to compute the local dielectric tensor of a plasma in a weakly inhomogeneous magnetic field. We find in this approximation the polarization of normal modes in the plasma, Cherenkov-curvature and Cherenkov-drift emissivities and growth rates.