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

四个太阳周期内产生强烈地磁暴的冕洞和活动区的统计研究

• 批准号: 2201767
• 负责人: Nishu Karna
• 金额: $ 41.67万
• 依托单位: Smithsonian Institution Astrophysical Observatory
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2201767&HistoricalAwards=false
• 关键词: Statistical; Study; Coronal; Holes; Active

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.

控制太阳活动的最基本属性之一是它的磁场。太阳的磁场由闭合和开放的磁力线组成，它们相互作用，突然发生，然后重新连接，影响等离子体在日冕物质抛射（CME）和太阳风中离开太阳的运动。太阳风可以通过日冕洞（CH）或具有开放场线的区域加速到高速。活动区（AR）是强闭合磁力线的区域，这些磁力线会引发爆发性事件，如CME和太阳耀斑。了解这些现象对于预测和防备空间天气对地球的有害影响至关重要。该项目将对四个完整的太阳活动周期进行统计研究。两名早期职业女性科学家将得到支持，三名本科生将通过这项研究得到指导。该项目详细研究冕洞-活动区相互作用在产生强地磁暴中的作用。两个科学问题将得到解决：（1）CH的位置和大小的演变可以作为一个代理，以了解IGS的发生和时间？(2)HSSs和CME之间的相互作用如何影响磁暴的强度？在过去，有限的研究已经暗示了这样的可能性，即偶数周期中的磁暴数量随着紧密CH-AR对数量的增加而增加，而奇数周期中的磁暴数量随着紧密CH-AR对数量的增加而减少。人们仍然不太清楚位置，规模和CH-AR相互作用如何影响火山爆发的潜在地理效应。因此，本项目将对四个完整的太阳活动周期（21-24）进行统计观测研究。他们将提供与所有IGS事件（265）相关的太阳风条件的概述及其特征的详细列表（速度、磁场、密度、温度、流动和磁压的平均值、磁场分量、最小Dst指数值），包括它们与活动区、冕洞、高速流的关联，该奖项反映了NSF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。