Whistler wave experiments in a bounded plasma

This research experimentally studied the propagation of an electromagnetic Whistler wave and its interaction with an electron beam. This required the development of a suitable plasma, the study of wave propagation in a bounded laboratory plasma and the development of an electron beam. The quiescent argon plasma had an electron density typically a few times 1012/cc with an electron temperature of about 3 eV. The plasma was produced with 1 kW at 2.90 Hz in a slow-wave structure in a one kilo-gauss 2:1 magnetic mirror field. Small loop antennas were used to launch and receive electromagnetic Whistler waves in the frequency range 0.5 less than ω/Ω/sub ce/ less than 0.9. The wave dispersion was measured and found to agree with the infinite cold plasma theory, although other modes were also present. An electron beam was developed to study a simple Landau interaction between the bounded Whistler wave and the beam. The interaction occurs when the parallel beam velocity is approximately equal to the phase velocity of the wave. Good agreement with theory was obtained when realistic beam distribution functions were used. A similar calculation was performed for the Whistler instability where the resonance condition is -vector k . vector v/sub b/ = Ω/sub ce/ - ω. These calculations related the transverse beam energy and the parallel velocity spread to the wave growth. The latter calculations could be used to develop an optimum electron beam to study this interaction in other experiments