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arXiv 2308.05366astro-ph.SR
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大太阳耀斑期间磁螺度和磁自由能的变化比率

Change ratios of magnetic helicity and magnetic free energy during major solar flares

Quan Wang, Mei Zhang, Shangbin Yang, Xiao Yang, Xiaoshuai Zhu

AI总结:

本文通过47个太阳耀斑样本,对比约束耀斑与爆发耀斑中磁螺度和磁自由能的变化比率,发现爆发耀斑的下降幅度显著更大,从而用观测数据验证了磁螺度近似守恒及CME带走磁螺度的理论。

摘要:

磁螺度是太阳物理学中的一个重要概念,许多理论陈述指出磁螺度在太阳耀斑和日冕物质抛射(CMEs)中具有重要作用。本文构建了一个包含47个太阳耀斑的样本,其中包括18个与CME无关的约束耀斑和29个与CME相关的爆发耀斑。我们计算了这47个耀斑前后磁螺度和磁自由能的变化比率。计算结果表明,磁螺度和磁自由能的变化比率在约束耀斑和爆发耀斑中表现出明显不同的分布。约束耀斑中磁螺度变化比率的中值为$-0.8$%,而爆发耀斑中该数值为$-14.5$%。对于磁自由能,约束耀斑的变化比率中值为$-4.3$%,而爆发耀斑中该数值为$-14.6$%。这一基于观测数据的统计结果与理论认识高度一致:如约束耀斑所示,磁螺度在磁重联过程中近似守恒;如爆发耀斑所示,CMEs将磁螺度从日冕中带走。

英文摘要:

Magnetic helicity is an important concept in solar physics, with a number of theoretical statements pointing out the important role of magnetic helicity in solar flares and coronal mass ejections (CMEs). Here we construct a sample of 47 solar flares, which contains 18 no-CME-associated confined flares and 29 CME-associated eruptive flares. We calculate the change ratios of magnetic helicity and magnetic free energy before and after these 47 flares. Our calculations show that the change ratios of magnetic helicity and magnetic free energy show distinct different distributions in confined flares and eruptive flares. The median value of the change ratios of magnetic helicity in confined flares is $-0.8$%, while this number is $-14.5$% for eruptive flares. For the magnetic free energy, the median value of the change ratios is $-4.3$% for confined flares, whereas this number is $-14.6$% for eruptive flares. This statistical result, using observational data, is well consistent with the theoretical understandings that magnetic helicity is approximately conserved in the magnetic reconnection, as shown by confined flares, and the CMEs take away magnetic helicity from the corona, as shown by eruptive flares.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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