SGER: Coronal Mass Ejection (CME) Initiations as a Result of Magnetic Helicity Accumulation in the Corona

PI提出了一项为期一年的调查，以研究和测试她与Co-PIs Low在之前NSF SHINE（国家科学基金会太阳能，日光层和行星际环境）奖的支持下开发的理论。张-洛理论指出，日冕物质抛射（CME）是日冕演化的自然最终产物，因为日冕中的磁螺旋度积累。这一理论将在理论和观测两方面进行研究和检验。提议者将首先研究MHD（磁流体动力学）猜想，即无力场可以包含的总磁螺旋度存在一个上限。如果存在这样一个上限，超过这个极限的磁螺旋度的积累将自然导致CME的爆发。提议者还将使用矢量磁场测量来研究几个活跃区域的磁螺旋度演变，以测试观测结果是否确实与CME发生在磁螺旋度显著积累时期的理论相一致。拟议的工作在智力上具有挑战性和创新性，因为它将改变科学家对日冕动力学的看法，并将需要制定新的办法来预测日冕物质抛射的起始，拟议工作的结果将对太阳界和空间界产生广泛的影响。这一努力将有助于理解CME的基本物理学，并为空间天气预报提供一个有前途的基于物理学的工具。

The PI proposes a one-year investigation to study and test a theory she developed with Co-PIs Low with support from a previous NSF SHINE (National Science Foundation Solar, Heliospheric, and INterplanetary Environment) award. The Zhang-Low theory states that coronal mass ejections (CMEs) are a natural end product of coronal evolution because of the accumulation of magnetic helicity in the corona. This theory will be investigated and tested both theoretically and observationally in this effort. The proposers will first investigate an MHD (magnetohydrodynamic) conjecture that there is an upper bound on the total magnetic helicity that a force-free field can contain. If such an upper bound exists, the accumulation of magnetic helicity in excess of this limit will naturally result in an eruption of a CME. The proposers will also use vector magnetic field measurements to study the magnetic helicity evolution in several active regions to test whether observations do show consistence with the theory that CMEs are occurring at times of significant accumulation of magnetic helicity. The proposed work is intellectually challenging and innovative, because it will change the way scientists view coronal dynamics and will require formulations of new approaches to CME-initiation prediction.The results of the proposed work will have a broad impact on solar and space community. This effort will contribute to the understanding of fundamental CME physics as well as provide a promising physics-based tool for space weather prediction.