PLASMA-DIFFUSION IN A SPACE-SIMULATION BEAM-PLASMA-DISCHARGE

Electron density and temperature profiles have been measured in a large‐facility beam‐plasma‐discharge (VB = 1.3 KeV, IB = 63 ma) at low pressure (P = 2‐4 (10−6)Torr) and low magnetic fields (B = 1.2 G). The results follow an exponential behavior and are found to be in good agreement with a simple diffusion model. The favorable comparison between theory and experiment yields the first estimate of cross‐field electron diffusion (De⊥(nom) = 2.2(106) cm²/sec) under conditions intended to simulate Spacelab‐borne beam‐plasma investigations. This value for De⊥ is orders of magnitude larger than would be expected for a cross‐field collisional diffusion process, a result which is identified with the turbulent state of collective beam‐plasma interactions. This paper is not subject to U.S. copyright.