THE MAGNETIC ENERGY–HELICITY DIAGRAM OF SOLAR ACTIVE REGIONS
THE MAGNETIC ENERGY–HELICITY DIAGRAM OF SOLAR ACTIVE REGIONS
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DOI：
10.1088/2041-8205/759/1/l4
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发表时间：
2012-09
期刊：
影响因子：
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通讯作者：
K. Tziotziou;M. Georgoulis;N. Raouafi
中科院分区：
文献类型：
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作者：
K. Tziotziou;M. Georgoulis;N. Raouafi
利用最近提出的一种适用于太阳活动区单矢量磁图的非线性无力方法，计算了对应于42个不同活动区的162个矢量磁图的瞬时自由磁能和相对磁螺旋度收支。我们发现在所研究的地区的自由磁能和相对磁螺旋度之间的统计鲁棒性，单调相关性。这种相关性意味着，除了自由磁能之外，磁螺旋度可能是主要太阳爆发的重要因素。爆发活动区与非爆发活动区在自由能和相对螺旋度上都有很好的分离，主要（至少M级）耀斑发生在自由能和相对螺旋度分别超过4 × 1031 erg和2 × 1042 Mx2的活动区。螺旋度阈值与典型日冕物质抛射的螺旋度含量的估计值吻合得很好。
Using a recently proposed nonlinear force-free method designed for single-vector magnetograms of solar active regions, we calculate the instantaneous free magnetic energy and relative magnetic helicity budgets in 162 vector magnetograms corresponding to 42 different active regions. We find a statistically robust, monotonic correlation between the free magnetic energy and the relative magnetic helicity in the studied regions. This correlation implies that magnetic helicity, in addition to free magnetic energy, may be an essential ingredient for major solar eruptions. Eruptive active regions appear well segregated from non-eruptive ones in both free energy and relative helicity with major (at least M-class) flares occurring in active regions with free energy and relative helicity exceeding 4 × 1031 erg and 2 × 1042 Mx2, respectively. The helicity threshold agrees well with estimates of the helicity contents of typical coronal mass ejections.