ELECTRON-CYCLOTRON WAVE-PROPAGATION, ABSORPTION, AND BACKSCATTER MEASUREMENTS IN A LABORATORY PLASMA

The subject of broadband microwave propagation and absorption processes and backscatter from objects immersed in a magnetized, finite plasma column is addressed. The propagation, absorption, and backscatter of electron cyclotron waves from an object in a warm, magnetized plasma are measured and compared with bounded vacuum hot plasma wave propagation, absorption, and ray tracing theory. The nonreciprocal nature of the electron cyclotron wave transmission and absorption in an anisotropic plasma is measured. A homodyne technique which isolates the scattering from a single object in the plasma from the scattering from all other objects in the plasma and the walls of the containment device is developed and utilized. The range of absorption frequencies and nonreciprocity of the transmission signal are shown to be well correlated with wave trajectories in the associated regions of the Clemmow-Mullaly-Allis (CMA) diagram. It is shown by experimental measurement, ray tracing and analysis of a vacuum boundary plasma column that quasi-parallel propagation of electron cyclotron waves near resonance is present and that the transverse wavenumber effects on propagation in the cylindrical plasma ((f(p)/f)2 greater than or similar to 6 f/f(ce) congruent-to 0.9) are small. An examination of cases in which damping occurs is shown to provide a stronger damping than WKB theory would predict, which is suggested by previous theoretical work. The experimental methods have a powerful potential for further basic plasma physics wave studies.