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Title: Flute instability of an ion-focused slab electron beam in a broad plasma

Journal Article · · Physical Review A. General Physics; (United States)
 [1]; ; ;  [2]; ;  [3]
  1. National Laboratory for High Energy Physics (KEK), 1-1 Oho, Tsukuba, Ibaraki 305 (Japan)
  2. Naval Research Laboratory, Washington, D.C. 20375 (United States)
  3. Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States)

An intense relativistic electron beam with an elongated cross section, propagating in the ion-focused regime through a broad, uniform, unmagnetized plasma, is shown to suffer a transverse flute instability. This instability arises from the electrostatic coupling between the beam and the plasma electrons at the ion-channel edge. The instability is found to be absolute and the asymptotic growth of the flute amplitude is computed in the frozen-field'' approximation and the large skin-depth limit. The minimum growth length is shown to be much less than the betatron period, with the consequence that focusing is rendered ineffective. It is further shown that growth is much reduced when the beam propagates through a narrow channel where the ion density greatly exceeds that of the surrounding plasma. In this limit, a modest spread in betatron frequency produces rapid saturation. The effect of plasma electron collisions is also considered. Results of beam breakup simulations are noted.

DOE Contract Number:
W-7405-ENG-48; AC03-76SF00098
OSTI ID:
7192524
Journal Information:
Physical Review A. General Physics; (United States), Vol. 46:10; ISSN 1050-2947
Country of Publication:
United States
Language:
English