The effect of electron re-population of the near-anode region on the measured anode fall voltage of a transverse discharge

Summary form only given, as follows. Results from previous experiments suggest that the magnitude of the steady-state population of electrons in the near-anode region controls the magnitude of the anode fall voltage in plasma discharges under the influence of a transverse magnetic field. Because the steady-state population of electrons in a given volume depends on the transverse electron flux entering that volume, reductions in the electron population in the near-anode region can in part be attributed to the reduction in the transverse diffusion coefficient which in general varies as 1/B (Bohm diffusion) or 1/B/sup 2/ (classical diffusion), where B is the magnitude of the transverse magnetic field. These large anode fall voltages limit the electrical efficiency and the lifetime of those plasma rockets that utilize E/spl times/B configurations to generate thrust. In an attempt to reduce the large anode fall voltages associated with transverse discharges, the use of a secondary discharge to introduce or generate more electrons in the near-anode region has been investigated. Changes in near-anode plasma properties such as electron density and local plasma potential driven by processes associated with the operation of the secondary discharge are measured via Langmuir probes and emission spectroscopy. In addition, from an energetics standpoint, the interaction between the secondary and primary discharge is accessed from electron energy distribution measurements. Actual changes in the anode fall driven anode power deposition is also presented as a function of the measured modifications made to the near-anode plasma.