A Statistical Survey of Hard X-ray Spectral Characteristics of Solar Flares with Two Footpoints
A Statistical Survey of Hard X-ray Spectral Characteristics of Solar Flares with Two Footpoints
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DOI：
10.1007/s11207-008-9193-9
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发表时间：
2008-05
期刊：
影响因子：
2.8
通讯作者：
P. Saint-Hilaire;S. Krucker;R. Lin
中科院分区：
文献类型：
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作者：
P. Saint-Hilaire;S. Krucker;R. Lin
利用RHESSI数据，我们分析了53次太阳耀斑期间的172个硬X射线（HXR）峰，这些峰具有双足点结构。用幂律拟合两个足点，我们发现光谱指数差Δγ大多在0到0.6之间，很少超过。足迹之间的不对称性没有观察到显着依赖于他们的平均日面位置，他们的相对位置相对于彼此，也不是他们的方向相对于太阳赤道。通过假设一个对称的加速过程，也很清楚，足点光谱指数和足点流量比的差异很少能归因于冕环两条腿之间的柱密度差异。我们的结果证实更好的磁镜陷阱的情况。此外，足迹不对称性更显着的峰值HXR通量的时间比平均在整个HXR爆发，这表明在个别HXR爆发的磁配置的演变。我们还观察到峰值50 keV通量和峰值GOES 1 - 8 μ m通道通量之间的线性相关性，并且HXR爆发持续时间似乎与环长度相关。
Using RHESSI data, we have analyzed 172 hard X-ray (HXR) peaks during 53 solar flares that exhibited a double-footpoint structure. Fitting both footpoints with power laws, we find that spectral index differences Δγrange mostly between 0 to 0.6, and only rarely go beyond. Asymmetries between footpoints were not observed to be significantly dependent on their mean heliographic position, their relative position with respect to each other, nor their orientation with respect to the solar equator. By assuming a symmetric acceleration process, it is also clear that differences in footpoint spectral indices and footpoint flux ratios can seldom be attributed to a difference in column densities between the two legs of a coronal loop. Our results corroborate better the magnetic mirror trap scenario. Moreover, footpoint asymmetries are more marked during times of peak HXR flux than when averaging over the whole HXR burst, suggesting that the magnetic configuration evolves during individual HXR bursts. We also observed a linear correlation between the peak 50-keV flux and the peak GOES 1 – 8 Å channel flux and that HXR burst duration seem correlated with loop length.