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Propagation of a laser beam in a time-varying waveguideThe propagation of an axisymmetric laser beam in a plasma column having a radially parabolic electron density distribution is reported. For the case of an axially uniform waveguide it is found that the basic characteristics of alternating focusing and defocusing beams are maintained. However, the intensity distribution is changed at the foci and outer-beam regions. The features of paraxial beam propagation are discussed with reference to axially varying waveguides. Laser plasma coupling is considered noting the case where laser heating produces a density distribution radially parabolic near the axis and the energy absorbed over the focal length of the plasma is small. It is found that: (1) beam-propagation stability is governed by the relative magnitude of the density fluctuations existing in the axial variation of the waveguides due to laser heating, and (2) for beam propagation in a time-varying waveguide, the global instability of the propagation is a function of the initial fluctuation growth rate as compared to the initial time rate of change in the radial curvature of the waveguide.
Document ID
19780067329
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Chapman, J. M. (Washington Univ. Seattle, WA, United States)
Kevorkian, J. (Washington, University Seattle, Wash., United States)
Date Acquired
August 9, 2013
Publication Date
September 1, 1978
Publication Information
Publication: Journal of Applied Physics
Volume: 49
Subject Category
PLASMA PHYSICS
Funding Number(s)
CONTRACT_GRANT: AF-AFOSR-76-3054
CONTRACT_GRANT: NGR-48-002-004
Distribution Limits
Public
Copyright
Other