Statistical Properties of Super-hot Solar Flares |
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Amir Caspi Submitted: 2013-12-02 13:09
We use RHESSI high-resolution imaging and spectroscopy observations from ~6 to 100 keV to determine the statistical relationships between measured parameters (temperature, emission measure, etc.) of hot, thermal plasma in 37 intense (GOES M- and X-class) solar flares. The RHESSI data, most sensitive to the hottest flare plasmas, reveal a strong correlation between the maximum achieved temperature and the flare GOES class, such that ?super-hot? temperatures >30 MK are achieved almost exclusively by X-class events; the observed correlation differs significantly from that of GOES-derived temperatures, and from previous studies. A nearly-ubiquitous association with high emission measures, electron densities, and instantaneous thermal energies suggests that super-hot plasmas are physically distinct from cooler, ~10?20 MK GOES plasmas, and that they require substantially greater energy input during the flare. High thermal energy densities suggest that super-hot flares require strong coronal magnetic fields, exceeding ~100 G, and that both the plasma beta and volume filling factor f cannot be much less than unity in the super-hot region.
Authors: Amir Caspi, Säm Krucker, R. P. Lin
Projects: RHESSI
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Publication Status: Published -- Caspi, A., Krucker, S., & Lin, R. P. 2014, ApJ, 781, 43; DOI 10.1088/0004-637X/781/1/43
Last Modified: 2014-05-30 13:59
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