MICROWAVE AND ELECTRON BEAM INTERACTIONS WITH A FINITE PLASMA.
STANFORD UNIV CALIF MICROWAVE LAB
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The purpose of the study was to investigate in detail, both theoretically and experimentally, the interaction between an electron beam and a finite plasma system. In the formal theoretical analysis, the plasma and beam are treated as frequency dependent dielectrics. Exact solutions to the Maxwell equations are obtained and the exact dispersion relation is obtained for a beam and plasma filling a waveguide. A propagation and field theory is developed, both analytically and numerically, for the slow waves on a plasma column without beam which has a radial variation in electron density and is in a dc magnetic field. It is predicted that it should be difficult to couple to the n 0 i.e., no angular dependence backward-wave modes, and this prediction is borne out experimentally. A gain theory is developed, both analytically and numerically, for a zero temperature finite beamplasma system in a finite dc magnetic field. The gain is predicted to be finite at all frequencies even though the temperature effects are neglected, the finiteness of the system being of far greater importance than the temperature effects. The attenuation of the slow waves on a plasma column is investigated both theoretically and experimentally. Author