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arXiv 1111.3881astro-ph.SR
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太阳黑子内半影的扭曲、扭动和螺旋度

Twist, Writhe & Helicity in the inner penumbra of a sunspot

Basilio Ruiz Cobo, Klaus G. Puschmann

摘要:

本工作的目的是确定扭曲,扭动,和自磁螺旋的半影细丝位于太阳黑子的内部半影。在这种程度上,我们反转的数据与分光偏振仪(SP)与SIR(斯托克斯反演响应函数的基础上)的代码登上日出。对于三维几何模型的构建,我们采用遗传算法最小化的磁场矢量和净磁流体动力学力的发散,因此,力免费的解决方案将达到如果可能的话。我们估计了两个代理的磁螺旋度在文献中经常使用的:无力参数和电流螺旋度项。我们发现,这两个代理人只是定性指标的本地扭曲的磁场在研究中的区域显着偏离的无力配置。局部扭转仅在两侧符号相反的明亮半影丝的边界处显示出显著值。这些位置与大电流精确相关。半影结构的平均扭曲(和扭动)很小。棘(背景中的黑色细丝)几乎没有扭动。棘内单位长度的扭动随管长的增加而减小。因此,当管更水平时,与脊柱内相关的管的轴较少扭曲。由于棘的扭动非常小,我们可以得出结论,只有当管包括棘内边界时,扭动才达到显著值。

英文摘要:

The aim of this work is the determination of the twist, writhe, and self magnetic helicity of penumbral filaments located in an inner Sunspot penumbra. To this extent, we inverted data taken with the spectropolarimeter (SP) aboard Hinode with the SIR (Stokes Inversion based on Response function) code. For the construction of a 3D geometrical model we applied a genetic algorithm minimizing the divergence of the magnetic field vector and the net magnetohydrodynamic force, consequently a force-free solution would be reached if possible. We estimated two proxies to the magnetic helicity frequently used in literature: the force-free parameter and the current helicity term. We show that both proxies are only qualitative indicators of the local twist as the magnetic field in the area under study significantly departures from a force-free configuration. The local twist shows significant values only at the borders of bright penumbral filaments with opposite signs on each side. These locations are precisely correlated to large electric currents. The average twist (and writhe) of penumbral structures is very small. The spines (dark filaments in the background) show a nearly zero writhe. The writhe per unit length of the intraspines diminishes with increasing length of the tube axes. Thus, the axes of tubes related to intraspines are less wrung when the tubes are more horizontal. As the writhe of the spines is very small, we can conclude that the writhe reaches only significant values when the tube includes the border of a intraspine.

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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