Theory

Current drive by high intensity, pulsed, electron cyclotron wave packets

¹ Plasma Science and Fusion Center, Massachusetts Institute of Technology , Cambridge MA 02139 USA
² National Technical University of Athens 157 73 Zographou Greece

^* e-mail: abhay@mit.edu
^** e-mail: kyriakos@central.ntua.gr
^*** e-mail: temkin@psfc.mit.edu

Published online: 25 March 2019

Abstract

The nonlinear interaction of electrons with a high intensity, spatially localized, Gaussian, electro-magnetic wave packet, or beam, in the electron cyclotron range of frequencies is described by the relativistic Lorentz equation. There are two distinct sets of electrons that result from wave-particle interactions. One set of electrons is reflected by the ponderomotive force due to the spatial variation of the wave packet. The second set of electrons are energetic enough to traverse across the wave packet. Both sets of electrons can exchange energy and momentum with the wave packet. The trapping of electrons in plane waves, which are constituents of the Gaussian beam, leads to dynamics that is distinctly different from quasilinear modeling of wave-particle interactions. This paper illustrates the changes that occur in the electron motion as a result of the nonlinear interaction. The dynamical differences between electrons interacting with a wave packet composed of ordinary electromagnetic waves and electrons interacting with a wave packet composed of extraordinary waves are exemplified.