Time-Dependent Plasma Behavior Triggered by a Pulsed Electron Gun under Conditions of Beam-Plasma-Discharge.
Abstract
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 (I(g), V(g), T(on)/T(off) = (34 ma, 1.9 keV, 80 ms/270 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 K/sec rate. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 13, 1981
- Accession Number
- ADA101952
Entities
People
- C. S. Lin
- Edward P. Szuszczewicz
Organizations
- United States Naval Research Laboratory