Quantifying Solar Magnetic Field Evolution and Its Relation to Eruptions

PI建议探索太阳喷发现象，例如日冕物质抛射(CMES)与活动区光球磁场流动和演化之间的关系。预测这些喷发事件的发生时间是空间气象研究中剩余的主要挑战之一。许多观察家报告说，在喷发活动区存在着旋转流和剪切流，它们可以为日冕磁场提供能量。此外，最近的数值模拟表明，包含扭曲或剪切磁场的活动区中的汇聚流动和磁通量抵消可以引发喷发。然而，与一般活动区流动一样，旋转、剪切运动和通量抵消只在少数情况下被定量研究。PI将测量至少30个活动区的流动、旋转、剪切、辐合和抵消，以系统地探索场演化和喷发行为之间的关系。她的样本是在太阳周期的过程中选择的，将由表现出不同类型行为的区域组成，从耀斑和日冕物质抛射，到灯丝消失，再到低活动。通过将局部相关跟踪(LCT)应用于SOHO/MDI和Gong+视线(LOS)光球层磁图，她将得出活动区流动，并测量旋转、剪切和会聚。当Solis色球LOS磁图可用时，提议者还将把LCT应用于Solis色球LOS磁图，这将为驱动太阳喷发的过程提供新的视角和进一步的约束。她将应用感应局部相关跟踪(ILCT)，这是一种最近开发的技术，使用LCT和磁感应方程来确定Solis矢量磁图中的三分量光球层速度场。利用笛卡尔极坐标变换，她将测量活动区磁性特征的旋转速度，并将其与LCT结果进行比较。此外，PI将量化通量抵消率，并研究它们在喷发事件发生前后的变化。主办方建议维护和加强加州大学伯克利分校现有的gong+相关网站。这项研究还将补充空间气象界其他人的CME建模工作。此外，这项调查可能会增强我们预测日冕物质抛射的能力，日冕物质抛射是空间天气最强大的驱动因素，在日地耦合系统中发挥着独特的作用。此外，这里开发的技术将有助于分析当前和未来的太阳磁强计的数据。

The PI proposes to explore the relationship between solar eruptive phenomena, e.g., coronal mass ejections (CMEs), and flows and evolution in active region photospheric magnetic fields. Predicting the onset of these eruptive events is one of the major remaining challenges in space weather research. Many observers have reported that rotational and shearing flows, which can contribute energy to the coronal magnetic field, are present in eruptive active regions. Further, recent numerical simulations suggest that converging flows and magnetic flux cancellation in active regions containing twisted or sheared magnetic fields can initiate eruptions. However, rotation, shearing motions, and flux cancellation, as with active region flows in general, have only been quantitatively investigated in a few case studies.The PI will measure flows, rotation, shear, convergence, and cancellation in at least 30 active regions, to systematically explore relationships between field evolution and eruptive behavior. Her sample, chosen over the course of the solar cycle, will consist of regions that exhibit different types of behavior, from flares and CMEs, to filament disappearances, to low activity. By applying local correlation tracking (LCT) to SOHO/MDI and GONG+ line-of-sight (LOS) photospheric magnetograms, she will derive active region flows, and measure rotation, shearing, and convergence. The proposer will also apply LCT to SOLIS chromospheric LOS magnetograms when they become available, which will provide new perspectives and further constraints on the processes driving solar eruptions. She will apply inductive local correlation tracking (ILCT), a recently developed technique using LCT and the magnetic induction equation, to determine three-component photospheric velocity fields from SOLIS vector magnetograms. Using Cartesian-to-polar transformations, she will measure the rotational velocities of active region magnetic features, and compare them with LCT results. In addition, the PI will quantify flux cancellation rates, and study their variation around the time of eruptive events. The PI proposes to maintain and enhance the existing GONG+ related website at UC Berkeley. This study will also complement CME modeling efforts by others in the space weather community. Further, this investigation may enhance our capability to predict CMEs, the most powerful drivers of space weather, which play a unique role in the coupled Sun-Earth system. In addition, techniques developed here will be useful in analysis of data from current and future solar magnetographs.