STATISTICAL PROPERTIES OF SUPER-HOT SOLAR FLARES

被引:63
作者
Caspi, Amir [1 ,2 ,4 ]
Krucker, Saem [2 ,3 ]
Lin, R. P. [2 ,4 ,5 ]
机构
[1] Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80303 USA
[2] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
[3] Univ Appl Sci & Arts Northwestern Switzerland, Sch Engn, Inst Technol 4D, CH-5210 Windisch, Switzerland
[4] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[5] Kyung Hee Univ, Sch Space Res, Seoul, South Korea
关键词
plasmas; radiation mechanisms: thermal; Sun: flares; Sun:; X-rays; gamma rays; X-RAY OBSERVATIONS; EMISSION MEASURE; LINE EMISSION; RHESSI; MODEL; ACCELERATION; TEMPERATURES; COMPONENT; PLASMA;
D O I
10.1088/0004-637X/781/1/43
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We use Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) high-resolution imaging and spectroscopy observations from similar to 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, similar to 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 similar to 100 G, and that both the plasma beta and volume filling factor f cannot be much less than unity in the super-hot region.
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页数:11
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