EAGER: Developing an Ab initio Model of Coronal Mass Ejections (CMEs) Incorporating All Forms of Helicity

这个为期两年的EAGER项目旨在改进目前的日冕物质抛射（CME）模型，该模型假设了一个简单的，扭曲的绳状结构的简化结构。目前的模型所假设的结构不足以捕捉其演变的全部复杂性。这个模型将包含一个更复杂的形式的轴，这个绳状结构。这一点很重要，因为CME的实际观测结果与简单模型并不相符。这种模型有可能导致一个显着改善预测的磁场方向时，CME击中地球，空间天气预报的一个关键问题。具体来说，该项目是开发一个数学模型，将扭曲到目前的扭曲磁通绳模型。这将被用来研究如何螺旋度是表现在不同的形式在一个日冕物质抛射，它如何从一种形式转变到另一种形式（从扭曲到扭动，例如），以及如何机制，如重新连接与头盔飘带可以理解的总螺旋度的守恒和变化的主导形式的螺旋度在日冕物质抛射。这样一个新的模型不仅将影响CME的现场测量分析，而且还将改变整个地球空间界处理CME启动问题以及CME驱动风暴期间太阳风-磁层耦合的方式。这也将提供一个洞察全球和本地结构的日冕物质抛射，因为他们的传播。该模型将用于开发重建代码，并使用真实的CME观测（例如DKIST）和现场测量对其进行验证。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

This two-year EAGER project seeks to improve on the current coronal mass ejection (CME) models which assume a simplified structure of a simple, twisted rope-like structure. The structure assumed in current models is insufficient for capturing the full complexity of their evolution. This model will incorporate a more complex form of the the axis of this rope-like structure. This is important because actual observations of CMEs do not match with the simple model. Such a model has the potential to lead to a significantly improved prediction of the magnetic field direction when the CME hits Earth, a key problem for space weather forecasting.Specifically, this project is to develop a mathematical model for incorporating writhe into the current twisted flux-rope models. This will be used to examine how helicity is manifested in different forms in a CME, how it transforms from one form to another (from twist to writhe, for example), and how mechanisms such as reconnection with helmet streamers may be understood in terms of conservation of total helicity and changes in the dominant form of helicity within a CME. Such a new model will not only influence the analysis of in situ measurements of CMEs, but also change the way the entire geospace community approaches the CME initiation problem as well as the solar wind-magnetosphere coupling during CME-driven storms. This will also provide an insight into both the global and local structure of CMEs as they propagate. This model will be used to develop a reconstruction code and validate it using real CME observations (for example by DKIST) and in situ measurements.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.