Theoretical Study of Dynamic Shield Response

摘要

A review is given of the theory and experimental confirmation of the dynamic shield response, a propagating ionization front generated by intense microwave irradiation of a non-uniform plasma. The original ray theory treatment of electromagnetic energy deposition was generalized to include the effects of reflection. It is shown that the development of a nonlinear response is not substantially affected by including reflection. Electron density profiles for the steadily propagating response are calculated with and without spatial dispersion near the plasma resonance or turning point. To obtain a more accurate model of energy deposition aroung the turning point, a solution of the Helmholtz equation given by Heading is employed. Profiles are computed by numerical integration of the electron growth equation. A detailed discussion of ionization processes in an rf discharge is presented. The importance of photoprocesses in producing precursor electrons is stressed, and a model of the precursor profile is developed. Finally, areas of possible application are suggested for utilizing the properties of the nonlinear shield response. (Author)