Evaluating (and Improving) Estimates of the Solar Radial Magnetic Field Component from Line-of-Sight Magnetograms
Evaluating (and Improving) Estimates of the Solar Radial Magnetic Field Component from Line-of-Sight Magnetograms
复制标题
DOI：
10.1007/s11207-017-1057-8
复制
发表时间：
2017-02-01
期刊：
影响因子：
2.8
通讯作者：
Wagner, E. L.
中科院分区：
文献类型：
--
作者：
Leka, K. D.;Barnes, G.;Wagner, E. L.
尽管对于许多太阳物理问题来说，理想的或有意义的边界是磁场 B-r 的径向分量，但最容易获得的测量是沿观察者视线的磁场分量 B-los。由于该分量仅等于视角恰好为零的径向分量，因此需要一些近似来估计所有其他观测位置处的 Br。在本研究中，将一种称为“mu 校正”的常见近似值（假设所有光球场都是径向的）与调用计算与观测到的 Blos 相匹配的势场的方法进行比较，从中恢复势场径向分量 B-r(pot)。我们证明，在所采用的数据分辨率下真正由径向场主导的区域中，mu 校正的性能即使不比势场方法更好，也是可以接受的。然而，研究还表明，对于任何包含水平场（即活性区域）的太阳能结构，势场方法可以更好地恢复径向场的强度和磁中性线的位置。
Although for many solar physics problems the desirable or meaningful boundary is the radial component of the magnetic field B-r, the most readily available measurement is the component of the magnetic field along the line of sight to the observer, B-los. As this component is only equal to the radial component where the viewing angle is exactly zero, some approximation is required to estimate Br at all other observed locations. In this study, a common approximation known as the "mu-correction", which assumes all photospheric field to be radial, is compared to a method that invokes computing a potential field that matches the observed Blos, from which the potential field radial component, B-r(pot) is recovered. We demonstrate that in regions that are truly dominated by a radially oriented field at the resolution of the data employed, the mu-correction performs acceptably if not better than the potential-field approach. However, it is also shown that for any solar structure that includes horizontal fields, i.e. active regions, the potential-field method better recovers both the strength of the radial field and the location of magnetic neutral line.