A Statistical Study of Coronal Holes and Active Regions Producing Intense Geomagnetic Storms over Four Solar Cycles

控制太阳活动的最基本的特性之一是它的磁场。太阳的磁场由封闭和开放的磁场线组成，它们相互作用、断裂和重新连接，影响着日冕物质抛射（cme）和太阳风中离开太阳的等离子体的运动。太阳风可以通过日冕洞（CHs）或开放磁场线的区域加速到高速。活动区（ARs）是具有强大的封闭磁力线的区域，可以发射诸如日冕物质抛射和太阳耀斑之类的喷发事件。了解这些现象对于预测和准备对地球有害的空间天气影响至关重要。该项目将对四个完整的太阳周期进行统计研究。通过这项研究，将支持两名早期职业女性科学家，并指导三名本科生。该项目详细研究了日冕洞-活动区相互作用在强地磁风暴（IGS）产生中的作用。将解决两个科学问题：(1)CH的位置和大小的演变是否可以作为理解IGS发生和时间的代理？(2)高磁暴与日冕物质抛射的相互作用如何影响地磁风暴的强度？在过去，有限的研究暗示了偶数周期地磁风暴的数量可能随着CH-AR对的增加而增加，而在奇周期中，地磁风暴的数量可能随着CH-AR对的增加而减少。目前尚不清楚位置、大小和CH-AR相互作用如何影响火山喷发的潜在地质效应。因此，本项目将进行覆盖4个完整太阳周期（21-24）的统计观测研究。他们将提供与所有IGS事件（265）相关的太阳风条件的概述和其特征的详细列表（速度，磁场，密度，温度，流量和磁压的平均值，磁场成分，最小Dst指数值），包括它们与活动区域，日冕洞，高速流和日冕物质抛射的关系。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

One of the most fundamental properties controlling activity on the Sun is its magnetic field. The Sun’s magnetic field consists of closed and open field lines that interact, snap, and reconnect, affecting the motion of plasma leaving the Sun in coronal mass ejections (CMEs) and through the solar wind. The solar wind can be accelerated to high speed through coronal holes (CHs), or regions with open field lines. Active regions (ARs) are regions of strong closed magnetic field lines that launch eruptive events such as CMEs and solar flares. Understanding these phenomena are crucial to predicting and preparing for harmful space weather effects on Earth. This project will perform a statistical study over four full solar cycles. Two early-career female scientists will be supported and three undergraduate students will be mentored through this research. The project is a detailed study of the role of coronal hole – active region interactions in the generation of intense geomagnetic storms (IGS). Two science questions will be addressed: (1) Can the evolution of CH location and size be used as a proxy to understand IGS occurrence and timing? (2) How does the interaction between HSSs and CMEs affect the strength of geomagnetic storms? In the past, limited studies have hinted at the possibility that the number of geomagnetic storms in even cycles increases with increasing number of close CH-AR pairs and decreases with increasing number of close CH-AR pairs in odd cycles. It is still not well understood how location, size and CH-AR interactions could influence the potential for an eruption to be geo-effective. Therefore, this project will make a statistical observational study covering four complete solar cycles (21-24). They will provide an overview of the solar wind conditions related to all IGS events (265) and a detailed list of their characteristics (mean values of speed, magnetic field, density, temperature, flow and magnetic pressures, components of the magnetic field, minimum Dst index values) including their association with active regions, coronal holes, high speed streams, and CMEs.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.