Time-Dependent Plasma Behavior Triggered by a Pulsed Electron Gun under Conditions of Beam-Plasma-Discharge.
NAVAL RESEARCH LAB WASHINGTON DC
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We have conducted a number of experiments intended to simulate spaceborne applications of energetic electron guns while exploring the in situ diagnostics of time-dependent beam-plasma behavior under pulsed electron gun conditions. The conditions include the beam-plasma-discharge BPD and the BPD afterglow that exists after gun-pulse termination. With electron gun characteristics set at Ig, Vg, TonToff 34 ma, 1.9 keV, 80 ms270 ms and a superimposed magnetic field at 1.5 gauss, the results show that 1 There is a three order-of-magnitude increase in plasma density within 5 ms of gun turn-on 2 During the pulse-ON time a quasi-steady-state BPD is maintained with characteristics identical to dc-BPD conditions 3 Plasma losses appear to be dominated by Bohm-like diffusion processes and finally 4 The afterglow can be characterized by an isodensity radial profile that decays with a 36 msec time constant and cools at a 3800 Ksec rate. Author
- Particle Accelerators