DIAGNOSTICS OF PULSED PLASMAS AND ELECTRON BEAM-PLASMA INTERACTIONS.
Final rept. for Feb 63-Jan 64,
POLYTECHNIC INST OF BROOKLYN N Y MICROWAVE RESEARCH INST
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A microwave phase bridge or interferometer was constructed and tested for the purpose of measuring high electron densities in pulsed plasmas. The initiation and growth, both in time and space, of a pulsed plasma 1 torr were studied by observations of intensity and line shape of several spectral lines. Measurement of Stark splitting yielded plots of electric field intensity and hence space charge distribution as functions of axial position and time. The discharge started near the anode and propagated towards the cathode, the electric field near the cathode reached 45 Kv cm in 25 nanoseconds and remained at about 58 Kv cm during almost the total pulse duration of 500 nanoseconds. The total optical radiation after 24 nanoseconds is only 5 percent of its value after 500 nanoseconds. A set-up was constructed for studying interactions between an electron beam and a plasma. The plasma was produced by e electron impact in the beam when the gas pressure was between 0.0001 and 0.01 torr. Some electronic gain was observed but no quantitative results were obtained because of experimental difficulties in maintaining a strong beam and a an appropriate plasma. Author