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The electron-cyclotron maser instability as a source of plasma radiationThe generation of continuum bursts from the sun at dm and m wavelengths (in particular, type IV bursts) via the electron-cyclotron-maser instability is examined. The maser instability can be driven by an electron distribution with either a loss-cone anisotropy or a peak at large pitch angles. For omega(p)/Omega(e) much greater than 1, the maser emission is produced by electrons interacting through a harmonic (cyclotron) resonance and is electrostatic, being in the upper hybrid mode at frequencies approximately equal to omega(p). Coalescence processes are required to convert the electrostatic waves into transverse radiation which can escape from the source region. Whether the resultant spectrum is nearly a smooth continuum or has a zebra-stripe pattern (both of which occur in type IV bursts) depends on the form of the electron distribution, inhomogeneities in the density and magnetic field, and whether the maser reaches saturation. For at least the case of some type IV dm bursts with fine structure, comparison with observations seems to indicate that the electrons producing the emission are more likely to have a loss-cone distribution, and that the maser instability is not at saturation.
Document ID
19870027489
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Winglee, R. M.
(Colorado Univ. Boulder, CO, United States)
Dulk, G. A.
(Colorado, University Boulder, United States)
Date Acquired
August 13, 2013
Publication Date
August 15, 1986
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 307
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
87A14763
Funding Number(s)
CONTRACT_GRANT: NSG-7287
CONTRACT_GRANT: NAGW-91
Distribution Limits
Public
Copyright
Other

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