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Full Record Details
Persistent URL
http://purl.org/net/epubs/work/11833424
Record Status
Checked
Record Id
11833424
Title
Laboratory astrophysics : investigation of planetary and astrophysical maser emission
Contributors
R Bingham (STFC Rutherford Appleton Lab., and Strathclyde Univ.)
,
DC Spiers (Strathclyde Univ.)
,
BJ Kellett (STFC Rutherford Appleton Lab.)
,
I Vorgul (St Andrews Univ.)
,
SL McConville (Strathclyde Univ.)
,
RA Cairns (St Andrews Univ.)
,
AW Cross (Strathclyde Univ.)
,
ADR Phelps (Strathclyde Univ.)
,
K Ronald (Strathclyde Univ.)
Abstract
This paper describes a model for cyclotron maser emission applicable to planetary auroral radio emission, the stars UV Ceti and CU Virginus, blazar jets and astrophysical shocks. These emissions may be attributed to energetic electrons moving into convergent magnetic fields that are typically found in association with dipole like planetary magnetospheres or shocks. It is found that magnetic compression leads to the formation of a velocity distribution having a horseshoe shape as a result of conservation of the electron magnetic moment. Under certain plasma conditions where the local electron plasma frequency ?pe is much less than the cyclotron frequency ?ce the distribution is found to be unstable to maser type radiation emission. We have established a laboratory-based facility that has verified many of the details of our original theoretical description and agrees well with numerical simulations. The experiment has demonstrated that the horseshoe distribution produces cyclotron emission at a frequency just below the local electron cyclotron frequency, with polarization close to X-mode and propagating nearly perpendicularly to the electron beam motion. We discuss recent developments in the theory and simulation of the instability including addressing radiation escape problems, and relate these to the laboratory, space, and astrophysical observations. The experiments showed strong narrow band EM emissions at frequencies just below the cold-plasma cyclotron frequency as predicted by the theory. Measurements of the conversion efficiency, mode and spectral content were in close agreement with the predictions of numerical simulations undertaken using a particle-in-cell code and also with satellite observations confirming the horseshoe maser as an important emission mechanism in geophysical / astrophysical plasmas. In each case we address how the radiation can escape the plasma without suffering strong absorption at the second harmonic layer.
Organisation
CLF
,
CI
,
STFC
Keywords
Funding Information
Related Research Object(s):
64158
Licence Information:
Language
English (EN)
Type
Details
URI(s)
Local file(s)
Year
Book Chapter or Section
In Microphysics of Cosmic Plasmas. Space Sciences Series of ISSI 47 edited by A Balogh, A Bykov, P Cargill, R Dendy, T Dudok de Wit, J Raymond, 619-637. Springer, 2013.
doi:10.1007/978-1-4899-7413-6_22
2013
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