Practical Determination of Force-Free Coronal Magnetic Fields

日冕磁场的性质对于理解和预测太阳耀斑至关重要。然而，日冕磁场不能直接测量。本文提出了一种利用矢量磁强计测量的光球层磁场计算无力日冕磁场的新方法。通过求解非线性无力场方程(具有非常数α)，得到了日冕场。该算法采用了一种新的无力场问题的形式，将场从一个势场演化为一个满足观测边界数据的无力场。场强要求满足边界磁通和边界电流密度法向分量的边界条件。计划使用夏威夷大学Mees太阳天文台的Stokes偏振仪和成像矢量磁力仪，研究将该方法应用于必然不完美的磁力仪数据时所涉及的实际考虑因素。

The nature of the coronal magnetic field is of central importance to the understanding and prediction of solar flares. The coronal magnetic field, however, cannot be measured directly. It is proposed to develop and apply a new method for computing the force-free coronal field from the photospheric magnetic field, as measured by a vector magnetograph. The coronal field is obtained by solving the nonlinear force-free equation (with non-constant alpha). The proposed algorithm employs a novel formulation of the force-free problem in which the field is evolved from a potential field to a force-free field which satisfies the observed boundary data. The field is required to satisfy boundary conditions on the magnetic flux and the normal component of the electric current density at the boundary. It is planned to study the practical considerations involved in the application of the method to necessarily imperfect magnetograph data, using the Stokes Polarimeter and the Imaging Vector Magnetograph at Mees Solar Observatory, University of Hawaii.