Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Beam-generated waves in a large plasma chamber

Journal Article · · IEEE Trans. Plasma Sci.; (United States)

Plasma waves generated in a large vacuum chamber (20 x 30 m) by an electron beam of energy 0.5 to 2 keV, are measured. Both pre-beam plasma discharge (pre-BPD) and beam plasma discharge (BPD) states are investigated. The measured waves fall roughly into three categories: 1) a low-frequency spectrum with f << f/sub ce/, f/sub rho/; 2) a whistler mode spectrum; and 3) a high-frequency spectrum. The extremely low frequency waves are shown to be surface waves on a (nonneutral) plasma column but a higher frequency part of the low-frequency spectrum was not thoroughly investigated. It is speculated that it also represents surface waves on a nonneutral column. Its measured properties are consistent with the lower hybrid drift instability. The whistler mode spectrum seems to be a Cerenkov resonance with the lower Trivelpiece-Gould mode. It does not seem to play an important role in modifying the particle distributions. The high frequency spectrum is a Cerenkov resonance with the upper Trivelpiece-Gould mode. It is responsible for the major perturbation of the beam energy in BPD.

Research Organization:
School of Physics and Astronomy, Univ. of Minnesota, Minneapolis, MN 55455
OSTI ID:
6742841
Journal Information:
IEEE Trans. Plasma Sci.; (United States), Journal Name: IEEE Trans. Plasma Sci.; (United States) Vol. PS-14:6; ISSN ITPSB
Country of Publication:
United States
Language:
English