第24太阳活动周X级耀斑的源区三维磁场演化

耀斑和日冕物质抛射（CME）是太阳大气中的典型爆发现象，其产生取决于源区磁场的位形及演化。因而，对源磁场的研究能够帮助人们理解耀斑和CME的形成及触发。本项目拟以第24太阳活动周的X级耀斑（部分有CME伴随）为样本，逐事件研究爆发源区三维磁场的演化，并从统计的角度总结出普遍规律。执行中，将针对每个事件的选定时段，以HMI光球矢量磁场数据为底边界，利用日冕磁场外推模型，逐时刻重构爆发源区的三维磁场；并结合成像观测，定位出与爆发相关的准分界面、磁绳等关键磁拓扑结构，研究其演化；同时计算磁自由能、衰减因数等磁性质参数，研究其演化。通过执行项目，预期了解与爆发相关的关键磁结构的演化细节，回答CME中磁绳的形成时间、束缚耀斑和爆发耀斑源磁场的区别等科学问题。从而深入理解相关等离子体物理过程，并为空间天气预报研究奠定一定的理论基础。

Flares and Coronal Mass Ejections (CMEs) are typical eruptions in the solar atmosphere, which are determined by the topology and evolution of their source magnetic fields. Thus, study on the magnetic sources will improve people's knowledge to the origin and triggering mechanisms of the eruptions. In this project, we will study the evolution of the three dimensional (3-D) source magnetic fields of X-class flares (some of which are accompanied by CMEs) in Solar Cycle 24, and try to draw some universal rules from the statistical view. For each event, we will reconstruct its source magnetic fields at each interested moment using HMI photospheric vector magnetic fields as boundaries, and locate the key structures for the eruption, such as flux ropes, quasi-separatrix layers, etc., then study their evolution. Magnetic parameters, such as magnetic free energy, decay index, etc., will also be calculated and studied. We will work on some scientific questions through this project, such as the details of the evolution of the key eruption structures, the formation time of the flux ropes in CMEs, and the differences between the source magnetic fields of confined and eruptive flares. Further, to comprehend the relevant plasma physical process, and shed light on the study of space weather forecast.