ACHIEVING SELF-CONSISTENT NONLINEAR FORCE-FREE MODELING OF SOLAR ACTIVE REGIONS
ACHIEVING SELF-CONSISTENT NONLINEAR FORCE-FREE MODELING OF SOLAR ACTIVE REGIONS
复制标题
实现太阳能活跃区域的自洽非线性无力建模
DOI：
10.1088/0004-637x/728/2/112
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
K. Leka
中科院分区：
文献类型：
--
作者：
M. Wheatland;K. Leka
基于2007年4月30日日出卫星观测得到的光球矢量磁图，考虑边界数据的不确定性，并采用改进的多仪器数据合并方法，对NOAA太阳活动区（AR）10953日冕磁场建立了非线性无力解。该解决方案首次展示了 Wheatland & Régnier 的“自洽”程序，其中包含了不确定性。自一致性过程解决了光球矢量磁图数据与无力模型不一致的问题，特别是垂直电流密度的边界条件被过度指定，并允许构造两种不同的非线性无力解。该过程会在一系列循环期间修改电流密度的边界条件，直到两个非线性无力解一致。因此，它构建了无力模型的精确单一解，其边界值接近但不完全匹配矢量磁图数据。包含不确定性可以在不确定性较小的点更紧密地保留边界条件。 AR 10953 获得的自洽解明显是非势能的，磁能 E/E0 ≈ 1.08，其中 E0 是参考势（无电流）磁场的能量。该自洽解决方案被证明对于每个周期中两个无力模型的构造细节的变化具有鲁棒性。这表明，如果包含矢量磁图边界数据的不确定性，则可以对 AR 进行可靠的非线性无力建模。
A nonlinear force-free solution is constructed for the coronal magnetic field in NOAA solar active region (AR) 10953 based on a photospheric vector magnetogram derived from Hinode satellite observations on 2007 April 30, taking into account uncertainties in the boundary data and using improved methods for merging multiple-instrument data. The solution demonstrates the “self-consistency” procedure of Wheatland & Régnier, for the first time including uncertainties. The self-consistency procedure addresses the problem that photospheric vector magnetogram data are inconsistent with the force-free model, and in particular that the boundary conditions on vertical electric current density are overspecified and permit the construction of two different nonlinear force-free solutions. The procedure modifies the boundary conditions on current density during a sequence of cycles until the two nonlinear force-free solutions agree. It hence constructs an accurate single solution to the force-free model, with boundary values close, but not matched exactly, to the vector magnetogram data. The inclusion of uncertainties preserves the boundary conditions more closely at points with smaller uncertainties. The self-consistent solution obtained for AR 10953 is significantly non-potential, with magnetic energy E/E0 ≈ 1.08, where E0 is the energy of the reference potential (current-free) magnetic field. The self-consistent solution is shown to be robust against changes in the details of the construction of the two force-free models at each cycle. This suggests that reliable nonlinear force-free modeling of ARs is possible if uncertainties in vector magnetogram boundary data are included.