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

磁场重联是控制太阳和地球之间空间天气的多个方面的基本过程。这一过程支配着太阳喷发事件，也对地球产生了影响。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。这一能力将通过提高验证空间天气模型的能力造福社会，并可很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，并在一次科学会议上组织一次关于多样性、公平和包容性的会议。这个提案项目探索的问题是：在太阳环境中重新连接期间等离子体的热力学历史和演化是什么？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，解释通常要么依赖于湍流，要么依赖于排气被慢模冲击限制的类Petschek结构。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。随着等离子体的膨胀和冷却，它可能会变得严重的过度电离。如果假定平衡，偏离电离平衡将导致对UV光谱和EUV图像的不准确解释，并且它们会在数量级水平上影响辐射冷却速率。然而，这些偏离也为探索等离子体的热历史提供了一个强大的手段。这项研究有可能促进对太阳喷发期间磁场重联区域热力学演化的认识，在这些区域，电离态可能远离平衡，而基于电离平衡假设的方法可能提供关于温度结构的不完整或误导性信息。MHD模拟中的在线电离计算可以显著扩展MHD模型的能力，并改进MHD模拟的观测预测。

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.