Measuring Active-Region Global Magnetic Twist for Prediction of Earthward Coronal Mass Ejections and their Geoeffectiveness

无需费力地将日冕X射线图像与矢量磁图对齐，也无需专家仔细检查核心场的X射线结构，这是朝着从矢量磁图实际预测日冕物质抛射（CME）及其地球效应迈出的重要一步。将对基于三种不同方法的核心磁场测定的可靠性进行经验评估。在强剪切和扭曲的情况下，这些解决横向磁场方向上180度模糊性的单独磁测方法将用一组20-30个活动区域进行测试，其中可以使用同时代的X射线数据来定义磁场方向。具有强烈剪切核心磁场的活动区域最有可能产生日冕物质抛射，并且了解核心磁场的方向对于预测地球行星际磁场（IMF）的方向非常重要。

Elimination of the need for painstaking alignment of coronal X-ray images with vector magnetograms and for expert scrutiny of the X-ray structure of the core field is an important step toward practical operational forecasting of Earth-directed Coronal Mass Ejections (CMEs) and their geoeffectiveness from vector magnetographs. An empirical evaluation of the reliability of core magnetic field determinations based upon three distinct methods will be carried out. These magnetogram-alone methods of resolving the 180 degree ambiguity in the direction of the transverse magnetic field in cases of strong shear and twist will be tested with a set of 20-30 active regions where coeval X-ray data can be used to define the field direction. The active regions that have strongly sheared core magnetic fields are most likely to produce CMEs, and knowledge of the orientation of this core field is important for anticipating the direction of the Interplanetary Magnetic Field (IMF) at Earth.