SHINE: Exploring Time-Dependent Ionization in Magnetic Reconnection During Solar Eruptions

SHINE：探索太阳喷发期间磁重联中的时间依赖性电离

• 批准号: 1723313
• 负责人: Chengcai Shen
• 金额: $ 35.95万
• 依托单位: Smithsonian Institution Astrophysical Observatory
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1723313&HistoricalAwards=false
• 关键词: SHINE; Exploring; Time; Dependent; Ionization

Magnetic reconnection is a fundamental process that governs multiple aspects of space weather between the Sun and Earth. This process governs the solar eruptive events as well has their effects at earth. The proposed research will enhance infrastructure for research and education by making new capabilities available for improving global models. This capability will benefit society by improving the ability to validate space weather models and can easily be applied to the study of other astrophysical systems. Members of the proposal team will mentor undergraduate summer interns, and organize a session on diversity, equity, and inclusion at a scientific meeting.This proposed program explores the question: What is the thermodynamic history and evolution of plasma during reconnection in the solar environment? The magnetic reconnection that drives solar flares and coronal mass ejections is much faster than predicted by classical mechanisms, and explanations generally rely on either turbulence or on a Petschek-like configuration with exhaust bounded by slow mode shocks. In either case, the rapid heating leaves the plasma drastically underionized. As plasma expands and cools, it can become severely overionized. Departures from ionization equilibrium will lead to inaccurate interpretation of UV spectra and EUV images if equilibrium is assumed, and they can affect the radiative cooling rate at the order of magnitude level. However, these departures also offer a powerful means of exploring the thermal history of the plasma. The proposed research has the potential to advance knowledge on thermodynamic evolution in magnetic reconnection regions during solar eruption, where the ionization state can be far from equilibrium and methods based on the assumption of ionization equilibrium can provide incomplete or misleading information about the temperature structure. The in-line ionization calculation within MHD simulations can significantly extend the capability of MHD models and improve observational predictions from MHD simulations.

磁重联是一个基本过程，它控制着太阳和地球之间空间天气的多个方面。这个过程控制着太阳爆发事件，也对地球产生影响。拟议的研究将通过提供改进全球模型的新能力来加强研究和教育的基础设施。这种能力将通过提高验证空间气象模型的能力而造福社会，并可容易地应用于其他天体物理系统的研究。提案团队的成员将指导本科生暑期实习生，并在科学会议上组织一次关于多样性，公平性和包容性的会议。这个拟议中的计划探讨的问题：什么是在太阳环境中重联等离子体的热力学历史和演变？驱动太阳耀斑和日冕物质抛射的磁场重联比经典机制预测的要快得多，解释通常依赖于湍流或类似Petschek的配置，其中排气被慢模式激波所限制。在任何一种情况下，快速加热都会使等离子体严重电离不足。随着等离子体膨胀和冷却，它会变得严重的过电离。如果假设电离平衡，电离平衡的假设将导致UV光谱和EUV图像的不准确解释，并且它们可以在数量级水平上影响辐射冷却速率。然而，这些偏离也提供了一个强大的手段，探索等离子体的热历史。拟议中的研究有可能在太阳爆发期间，在磁重联区域，电离状态可以远离平衡和电离平衡假设的基础上的方法可以提供不完整的或误导性的信息的温度结构的热力学演化的知识。MHD模拟中的在线电离计算可以显着扩展MHD模型的能力，并改善MHD模拟的观测预测。

项目成果

The origin of underdense plasma downflows associated with magnetic reconnection in solar flares

• DOI: 10.1038/s41550-021-01570-2
• 发表时间: 2021-11
• 期刊: Nature Astronomy
• 影响因子: 14.1
• 作者: Chengcai Shen;Bin Chen;K. Reeves;Sijie Yu;V. Polito;Xiao-yang Xie

Nonequilibrium Ionization Effects on Solar EUV and X-Ray Imaging Observations

• DOI: 10.3847/1538-4357/ab24bb
• 发表时间: 2019-07-10
• 期刊: ASTROPHYSICAL JOURNAL
• 影响因子: 4.9
• 作者: Lee, Jin-Yi;Raymond, John C.;Kim, Yeon-Han
• 通讯作者: Kim, Yeon-Han

The Dynamical Behavior of Reconnection-driven Termination Shocks in Solar Flares: Magnetohydrodynamic Simulations

太阳耀斑中重新连接驱动的终止激波的动力学行为：磁流体动力学模拟

• DOI: 10.3847/1538-4357/aaeed3
• 发表时间: 2018-12
• 期刊: Astrophysical Journal
• 影响因子: 4.9
• 作者: Shen Chengcai;Kong Xiangliang;Guo Fan;Raymond John C.;Chen Bin
• 通讯作者: Chen Bin

Radio Spectroscopic Imaging of a Solar Flare Termination Shock: Split-band Feature as Evidence for Shock Compression

• DOI: 10.3847/1538-4357/ab3c58
• 发表时间: 2019-08
• 期刊: The Astrophysical Journal
• 作者: B. Chen 陈;Chengcai 彩 Shen 沈呈;K. Reeves;F. Guo 郭;Sijie 捷 Yu 余思