Collisionless Plasma Flow over a Conducting Sphere

A nonlinear interaction between the whistler mode wave packet and resonantparticles is considered. An evolution of the packet’s shape is investigated in detail. Nonlinear effects produced by the interaction of whistlers with resonant particles have been discussedin a large number of papers (e.g. Roux and Solomon, 1970; Coriniti et al., 1971; Bud’ko ef al., 1971).However, either packets with rather broad spectrum to which random phase approximation is applicable,or monochromatic plane waves of infinite length were considered. In the present paper we deal with whistlermode (W.M.) packets, which have such a narrow spectrum, that they cannot be treated in the randomphase approximation. For experimental evidence for the significance of such cases see. e.g., Coroniti ef al.“)Our results are also applicable to VLF waves, radiated by transmitters and propagating along the geo-magnetic field lines in the upper ionosphere and magnetosphere.The numerical investigation of particle trajectories in W.M. packet was performed by Ashour-Abdalla.‘P)We use an analytical asymptotic method which permits us to elucidate some new features of nonlinearevolution of the packet in stable and unstabIe plasmas.