Suzaku/WAM and RHESSI Observations of Non-thermal Electrons in Solar Microflares
Suzaku/WAM and RHESSI Observations of Non-thermal Electrons in Solar Microflares
复制标题
太阳微耀斑中非热电子的朱雀/WAM 和 RHESSI 观测
DOI：
10.1088/0004-637x/765/2/143
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发表时间：
2013
期刊：
影响因子：
4.9
通讯作者：
R. P.
中科院分区：
文献类型：
--
作者：
Ishikawa;S.;Rrucker;S.;Ohno;M.;Lin;R. P.
我们报告的硬X射线光谱观测的太阳微耀斑的宽带全天监测（WAM），在朱雀卫星上，和RHESSI。WAM瞬态数据在大视场（~ 2π sr）上提供宽能带（50 keV-5 MeV）谱，时间分辨率为1 s。WAM作为硬X射线太阳耀斑监测器是有吸引力的，由于其大的有效面积（100 keV时为800 cm 2，比RHESSI大13倍）。特别是，这使得有可能在微耀斑中寻找远低于RHESSI背景的高能发射。WAM太阳耀斑列表包含六个GOES B级微耀斑，这些微耀斑是RHESSI在2005年7月和2010年3月发射朱雀之间同时观测到的。在100千电子伏，检测到的WAM通量超过200倍低于典型的RHESSI仪器背景计数率。RHESSI和WAM非热谱与光子谱指数在3.3和4.5之间的单一幂律非常一致。在第二步中，我们还搜索了RHESSI微耀斑列表中应该被WAM检测到的事件，假设RHESSI看到的非热幂律发射扩展到> 50 keV。在2005年7月至2007年2月期间的12次可探测事件中，有11次确实被WAM看到。这表明微耀斑，类似于常规耀斑，可以将电子加速到至少100 keV的能量。
We report on hard X-ray spectroscopy of solar microflares observed by the Wide-band All-sky Monitor (WAM), on board the Suzaku satellite, and by RHESSI. WAM transient data provide wide energy band (50 keV–5 MeV) spectra over a large field of view (∼ 2π sr) with a time resolution of 1 s. WAM is attractive as a hard X-ray solar flare monitor due to its large effective area (∼ 800 cm 2 at 100 keV,∼ 13 times larger than that of RHESSI). In particular, this makes it possible to search for high energy emission in microflares that is well below the RHESSI background. The WAM solar flare list contains six GOES B-class microflares that were simultaneously observed by RHESSI between the launch of Suzaku in 2005 July and 2010 March. At 100 keV, the detected WAM fluxes are more than∼ 20 times below the typical RHESSI instrumental background count rates. The RHESSI and WAM non-thermal spectra are in good agreement with a single power law with photon spectral indices between 3.3 and 4.5. In a second step, we also searched the RHESSI microflare list for events that should be detectable by WAM, assuming that the non-thermal power-law emission seen by RHESSI extends to> 50 keV. From the 12 detectable events between 2005 July and 2007 February, 11 were indeed seen by WAM. This shows that microflares, similar to regular flares, can accelerate electrons to energies up to at least 100 keV.