Heterodyne detection of lower hybrid waves in a plasma by microwave scattering

Abstract

Lower hybrid waves externally excited by a meander-line slow-wave antenna were observed by scattering of 70 GHz microwaves. The spatial distribution and wavenumber spectrum of lower hybrid waves travelling in a linear plasma were obtained. The up-shifted and down-shifted scattering signals from the incident microwave were separately observed by a phase locked heterodyne receiver. These observations make clear not only the magnitude but also the direction of the wavenumber vector. These are consistent with the auxiliary wave measurements using an electrostatic probe.