DISTRIBUTION OF ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS
DISTRIBUTION OF ELECTRIC CURRENTS IN SOLAR ACTIVE REGIONS
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DOI：
10.1088/2041-8205/782/1/l10
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发表时间：
2014-01
期刊：
影响因子：
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通讯作者：
Tibor Torok;J. Leake;Viacheslav S. Titov;V. Archontis;Zoran Miki'c;M. Linton;K. Dalmasse;Guillaume Aulanier;B. Kliem
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文献类型：
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作者：
Tibor Torok;J. Leake;Viacheslav S. Titov;V. Archontis;Zoran Miki'c;M. Linton;K. Dalmasse;Guillaume Aulanier;B. Kliem
关于太阳活动区的电流是否被中和的问题一直存在着长期的争论。也就是说，连接活动区极性的主（或直接）日冕电流是否被总价值相等且方向相反的屏蔽（或返回）电流包围。关于这个问题，理论和观测都还没有完全得出结论，令人惊讶的是，数值模拟几乎没有被用来解决它。在这里，我们通过考虑一个三维磁流体动力学模拟的出现，一个亚光球，电流中性磁通绳进入太阳大气层的双极活动区形成过程中的电流的演变进行量化。我们发现，一个强大的偏离电流中和发展的同时，发病的显着通量出现到日冕，伴随着大量的磁剪切沿着的活动区的极性反转线的发展。在区域形成和磁通出现停止后，区域中心的强磁场仅由直流电流连接，总直流电流比总返回电流大几倍。这些结果表明，活跃地区，日冕物质抛射和耀斑的主要来源，出生与大量的净电流，与最近的观测结果一致。此外，他们支持喷发模型，采用喷发前磁场包含这样的电流。
There has been a long-standing debate on the question of whether or not electric currents in solar active regions are neutralized. That is, whether or not the main (or direct) coronal currents connecting the active region polarities are surrounded by shielding (or return) currents of equal total value and opposite direction. Both theory and observations are not yet fully conclusive regarding this question, and numerical simulations have, surprisingly, barely been used to address it. Here we quantify the evolution of electric currents during the formation of a bipolar active region by considering a three-dimensional magnetohydrodynamic simulation of the emergence of a sub-photospheric, current-neutralized magnetic flux rope into the solar atmosphere. We find that a strong deviation from current neutralization develops simultaneously with the onset of significant flux emergence into the corona, accompanied by the development of substantial magnetic shear along the active region's polarity inversion line. After the region has formed and flux emergence has ceased, the strong magnetic fields in the region's center are connected solely by direct currents, and the total direct current is several times larger than the total return current. These results suggest that active regions, the main sources of coronal mass ejections and flares, are born with substantial net currents, in agreement with recent observations. Furthermore, they support eruption models that employ pre-eruption magnetic fields containing such currents.