标题： 光球和日冕磁场中分形结构的相关性 显示英文标题

标题： The correlation of fractal structures in the photospheric and the coronal magnetic field

摘要： 这项工作研究了光球磁场模式的分形性质与太阳活动区日冕磁场的分形性质之间的关系。我们的结果显示，当使用非线性力自由外推时，所观测到的二维光球结构的分形维数和日冕中推断出的不稳定体积之间没有相关性。 这一结果独立于以下两种努力：（1）使光球磁场更接近非线性力自由平衡状态；（2）省略模型磁场体积的下部分，这部分几乎完全被不稳定体积占据。 只有在零级（潜在的下限）电流自由（势场）磁场外推时，光球和日冕磁场特征的分形维数之间才显示出显著的相关性。 我们得出结论，在非线性力自由限制条件下，从光球非力自由场到日冕力自由场的复杂过渡阻碍了二维光球模式与其在日冕中的三维对应物之间分形维数的任何直接相关性。 显示英文摘要

摘要： This work examines the relation between the fractal properties of the photospheric magnetic patterns and those of the coronal magnetic fields in solar active regions.Our results show no correlation between the fractal dimensions of the observed 2d photospheric structures and the extrapolated unstable volumes in the corona, when nonlinear force-free extrapolation is used. This result is independent of efforts to (1) bring the photospheric magnetic fields closer to a nonlinear force-free equilibrium and (2) omit the lower part of the modeled magnetic field volume that is almost completely filled by unstable volumes. A significant correlation between the fractal dimensions of the photospheric and coronal magnetic features is only observed at the zero level (lower limit) of approximation of a current-free (potential) magnetic field extrapolation. We conclude that the complicated transition from photospheric non-force-free fields to coronal force-free ones hampers any direct correlation between the fractal dimensions of the 2d photospheric patterns and their 3d counterparts in the corona at the nonlinear force-free limit.