太阳爆发暗条及其所形成CME性质的研究

Space weather, which is originated from solar activities, is straightly threatening the earth environment. Among them, the solar flares and corona mass ejections (CMEs) are the most violet ones. The active filaments are always became the key point of their eruptions, i. e., in common interpretations, the bright cores of CMEs are considered as the erupting filaments. Moreover, in the CHSKE model, the eruptive filaments are also treated as the triggers of flares. Thus, studies of active filaments are important for connecting these two activities. It means the deeper we understanding the solar activities, more accurate forecasting it will be. In this proposal, the records of active filaments in the Heliophysics Event Knowledgebase (HEK) will be used in the statistic analysis. Firstly, we will associate them with the observation of the space telescopes including SDO, STEREO and GOES and the ground-based telescopes including NVST, Onset and GST to understand the relationship between the trigger and accelerate mechanism, such as instabilities and magnetic reconnection, of CMEs and filaments properties, e. g., types, magnetic configurations, size and so on. Next, in order to understand which is the main factor for determining the speed of CMEs, we will obtain many factors of eruptive filaments, such as filament magnetic configurations, magnetic strength, intensity of associating flares and the coupling factors from previous ones, to build the relationship of them. At last we will do some deep analysis or even numerical simulations for some complicate eruptions, and hope that will provide some new views of the trigger mechanism of CMEs.

太阳活动驱动的空间天气变化会对地球空间环境产生严重影响。其中，影响最为剧烈的活动为太阳耀斑与日冕物质抛射（CME），因此，深入了解这些太阳爆发性活动，可以帮助我们提升空间天气预报的准确性。CME的发生通常伴随着爆发暗条，一则，暗条的运动能够反映CME的初始加速过程；二则，暗条的物质将形成CME的亮核。因此对爆发暗条的研究是理解CME的重要线索。本项目将采用日球事件数据库（HEK）所收集的暗条爆发事件，并结合SDO、STEREO和GOES等空间望远镜与NVST、Onset和GST等地面望远镜，统计大量爆发事件，尝试将爆发的诱因和加速机制与暗条类型、尺度以及磁场结构等性质联系起来，寻求其相关性。继而，我们将从包括暗条通道磁场强度、自由能和伴随耀斑强度等多种因素、以及它们的复合因素中，找出影响CME抛射速度的决定因素。最后我们将对个别复杂的事例进行详细分析，探索传统模型以外可能的CME爆发机制。

太阳爆发活动是空间天气的主宰，而其中日冕物质抛射是其中最为强烈的爆发活动。本项目着眼于太阳暗条引起的日冕物质抛射现象的触发机制，通过统计及个例分析的手段研究暗条在爆发初期是通过何种机制——由磁重联还是磁流体不稳定性——来导致爆发。在后续的爆发过程中又是通过何种机制来促进其加速或制约其爆发最终是否形成日冕物质抛射。本项目经过三年研究获得了如下的几个重要结果：1、在爆发的初始阶段，磁流体不稳定性对产生爆发和最终形成日冕物质抛射会带来更加关键的作用；2、在爆发初始阶段的磁重联在特殊磁场位型下不仅不能决定是否产生日冕物质抛射，甚至可能制约其爆发；3、在爆发传播过程中，磁绳与周围磁场结构重联能够为磁绳爆发提供帮助，促进爆发过程。以上结论对承载暗条的磁绳结构是否能够产生日冕物质抛射这一关键问题带来一些新看法，尤其是磁重联在爆发时甚至能阻断爆发是全新的发现。