Helicons in the Presence of an AC Field in a Superlattice Plasma of Finite Layer Thickness

Abstract

Helicon propagation in superlattices is examined in the presence of an externally applied ac electric field. Particle trajectories in perturbed and unperturbed coordinates in the presence of the applied ac field are determined and used for evaluating the perturbed distribution function, conductivities, and dielectric tensors. These results are used to find the dispersion relation for a superlattice structure. Illustrations are given for a superlattice structure subjected to various ac field amplitudes and frequencies. The earlier results for helicon mode propagation are recovered when the externally applied ac field is reduced to zero along the superlattice growth axis. It is observed that the ac field frequencies significantly affect the branch‐folding and propagation characteristics rather than the amplitudes of the signal. Application of this study for visualizing many observable effects through experiments and computer simulations are suggested. Copyright © 1993 WILEY‐VCH Verlag GmbH & Co. KGaA