Improving Models to Better Represent the Complex Structure of Coronal Mass Ejections

点击翻译按钮获取中文摘要

This award is to support the investigation of Coronal Mass Ejection (CME) structures. CMEs are eruptions from the sun or storms which release billions of tons of material and strong electromagnetic fields into the solar system. When directed at Earth, they typically take about three days to arrive, however, very powerful storms can arrive in as few as 18 hours. This gives very little lead time in which to prepare for disruptions to satellites and to power grids. CMEs change characteristics as they move through the solar system. Therefore, understanding the structure and how these changes occur is very important for understanding when a CME will arrive at Earth and how it will impact Earth’s magnetic field and our essential assets. This project supports an early career scientist for their first time as PI.Even though the internal structure of CMEs has been the main focus of numerous studies over the past several decades, there are still large ambiguities regarding their structure. In spite of having decades of in situ measurements of CMEs in the near-Earth environment, shortcomings of the existing techniques, codes and models limit what we can learn about these important and complex structures. The current lack of understanding can be summarized into two main points: (1) limitations of the measurements themselves, and more importantly, (2) limitations due to the assumptions made to analyze these measurements. The majority of performed studies still assume a cylindrical symmetric Linear force-free (Lundquist) solution. At the same time, new remote observations of CMEs in their infancy at the Sun and later on, as they propagate, reveal how complex these structures are. This project will incorporate more of the physical features of observed and simulated CMEs into fitting and reconstruction codes, including their expansion and evolution over time (aging), the effect of spacecraft trajectory, and the existence of more complex magnetic field structures than just a well-organized circular twisted magnetic flux rope.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.