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Impulsive phase solar flare X-ray polarimetry

Author
Emslie, A. Gordon
Published
JAN 1, 1986.
Physical Description
1 electronic document
Additional Creators
Novick, Robert and Chanan, Gary
Online Version

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Unclassified, Unlimited, Publicly available.
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Summary
The pioneering observational work in solar flare X-ray polarimetry was done in a series of satellite experiments by Tindo and his collaborators in the Soviet Union; initial results showed high levels of polarization in X-ray flares (up to 40%), although of rather low statistical significance, and these were generally interpreted as evidence for strong beaming of suprathermal electrons in the flare energy release process. However, the results of the polarimeter flown by the Columbia Astrophysics Laboratory as part of the STS-3 payload on the Space Shuttle by contrast showed very low levels of polarization. The largest value (observed during the impulsive phase of a single event) was 3.4% + or - 2.2%. At the same time but independent of the observational work, Leach and Petrosian (1983) showed that the high levels of polarization in the Tindo results were difficult to understand theoretically, since the electron beam is isotropized on an energy loss timescale. A subsequent comparison by Leach, Emslie, and Petrosian (1985) of the impulsive phase STS-3 result and the above theoretical treatment shows that the former is consistent with several current models and that a factor of approximately 3 improvement in sensitivity is needed to distinguish properly among the possibilities.
Other Subject(s)
Collection
NASA Technical Reports Server (NTRS) Collection.
Note
Document ID: 19870012356.
Accession ID: 87N21789.
NASA. Goddard Space Flight Center Rapid Fluctuations in Solar Flares; p 47-62.
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No Copyright.
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