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Title: Measurements of the divergence of fast electrons in laser-irradiated spherical targets

In recent experiments using directly driven spherical targets on the OMEGA laser system, the energy in fast electrons was found to reach ∼1% of the laser energy at an irradiance of ∼1.1 × 10{sup 15} W/cm{sup 2}. The fraction of these fast electrons absorbed in the compressed fuel shell depends on their angular divergence. This paper describes measurements of this divergence deduced from a series of shots where Mo-coated shells of increasing diameter (D) were suspended within an outer CH shell. The intensity of the Mo–Kα line and the hard x-ray radiation were found to increase approximately as ∼D{sup 2}, indicating wide divergence of the fast electrons. Alternative interpretations of these results (electron scattering, radiation excitation of Kα, and an electric field due to return current) are shown to be unimportant.
Authors:
; ; ; ; ;  [1]
  1. Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)
Publication Date:
OSTI Identifier:
22220619
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 9; 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; CURRENTS; ELECTRIC FIELDS; ELECTRONS; FUELS; HARD X RADIATION; INERTIAL CONFINEMENT; IRRADIATION; LASERS; PLASMA DIAGNOSTICS; RADIANT FLUX DENSITY; SPHERICAL CONFIGURATION; THERMONUCLEAR IGNITION; THERMONUCLEAR REACTORS