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Title: Self-pinched transport of a high ν/γ electron beam

The self-pinched transport of a 0.5 MeV, 18 kA cylindrical electron beam has been studied experimentally and computationally. The relatively low voltage and high current required for materials surface modification applications leads to complicated beam dynamics as the Alfven limit is approached. Transport and focusing of the high ν/γ beam was done in a sub-Torr, neutral gas-filled, conducting tube in the ion-focused regime. In this regime, beam space charge forces are progressively neutralized to allow focusing of the beam by its self-magnetic field. The beam exhibits stable envelope oscillations as it is efficiently and reproducibly propagated for distances greater than a betatron wavelength. Experimental results follow the trends seen in 2-D particle-in-cell simulations. Results show that the input electron beam can be periodically focused to a peaked profile with the beam half-current radius decreased by a factor of 2.84. This results in an increase of a factor of 8 in beam current density. This focusing is sufficient to produce desired effects in the surface layers of metallic materials.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. U.S. Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Ave., SW, Washington DC 20375 (United States)
  2. Voss Scientific, 418 Washington St. SE, Albuquerque, New Mexico 87108 (United States)
  3. Commonwealth Technology Inc., 5875 Barclay Drive, Alexandria, Virginia 22315 (United States)
Publication Date:
OSTI Identifier:
22218549
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 10; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BEAM CURRENTS; BEAM DYNAMICS; BEAM-PLASMA SYSTEMS; ELECTRIC POTENTIAL; ELECTRON BEAMS; ION BEAMS; MAGNETIC FIELDS; MEV RANGE; OSCILLATIONS; PERIODICITY; PINCH EFFECT; PLASMA FOCUS; PLASMA SIMULATION; PLASMA WAVES; SPACE CHARGE; SURFACES