Quantifying Solar Magnetic Field Evolution and Its Relation to Eruptions

量化太阳磁场演化及其与喷发的关系

• 批准号: 0451438
• 负责人: Yan LI
• 金额: --
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0451438&HistoricalAwards=false
• 关键词: Quantifying; Solar; Magnetic; Field; Evolution

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.

PI建议探索太阳爆发现象之间的关系，例如，日冕物质抛射（CME），以及活动区光球磁场的流动和演化。预测这些爆发事件的发生是空间气象研究中仍然存在的主要挑战之一。许多观测者报告说，在喷发活跃区存在旋转流和剪切流，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域中的会聚流和磁通量抵消可以引发喷发。然而，旋转，剪切运动和通量抵消，与一般的活动区流，只有在少数情况下进行了定量研究。PI将测量至少30个活动区的流动，旋转，剪切，收敛和抵消，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CME到暗条消失，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）光球磁图，她将导出活动区域流，并测量旋转，剪切和收敛。提议者还将在SOLIS色球视线磁图可用时将LCT应用于这些磁图，这将为驱动太阳爆发的过程提供新的视角和进一步的限制。她将应用感应局部相关跟踪（ILCT），最近开发的技术，使用LCT和磁感应方程，以确定三分量光球速度场的SOLIS矢量磁图。她将使用笛卡尔到极坐标的转换，测量活动区域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，并研究其在喷发事件发生前后的变化。PI建议维护和增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天气界其他人的CME建模工作。此外，这项研究可能会提高我们预测CME的能力，CME是空间天气最强大的驱动因素，在耦合的太阳-地球系统中发挥着独特的作用。此外，这里开发的技术将是有用的数据分析从当前和未来的太阳磁。