Radiation from a magnetic line source in a moving isotropic plasma

Abstract

The problem of radiation from an electric dipole placed in a moving isotropic plasma has been studied by Lee and Papas for a special case where the velocity of the plasma is relatively small compared with the light velocity in vacuum. In this paper, we consider a radiation problem for a more general case where no restriction is imposed on the magnitude of the velocity of the plasma, and for a case where the source of radiation is assumed to be a magnetic line source.We investigate theoretically the effects of the movement of the plasma on the far-zone radiated electromagnetic fields and on the radiation pattern. The results show that the Poynting vector has a circumferential component, and therefore the direction of radiated-energy flow deviates from the radial direction, and it depends on the magnitude of the velocity of the plasma and on the angle between the position vector of an observer and the velocity vector of the plasma. Some numerical examples of its deviation and of the radiation pattern are illustrated.