SHINE: Theoretical Investigation of Small Scale Structure in Solar Flare Current Sheets

SHINE：太阳耀斑电流片中小尺度结构的理论研究

• 批准号: 1358342
• 负责人: Chengcai Shen
• 金额: $ 34.26万
• 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: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1358342&HistoricalAwards=false
• 关键词: SHINE; Theoretical; Investigation; Small; Scale

Magnetic reconnection is a fundamental physical space plasma process that is the driver of solar eruptions. A detailed understanding of magnetic reconnection, therefore, is an important component of understanding the physical processes responsible for space weather at Earth. Magnetic reconnection governs the dynamics and heating of other astrophysical plasmas as well. The process occurs on length scales much shorter than can be observed remotely, but the released energy and changes in magnetic structure have important global consequences. The objective of this project is to perform numerical simulations of magnetic reconnection in the solar atmosphere that result in predictions that are suitable for comparison with solar observations. The results will provide new understanding of the observational signatures of reconnection and new understanding of the role of small-scale structures in rapid reconnection and particle acceleration. The project includes significant science education and public outreach components. Members of the proposal team will mentor undergraduate summer interns. Funding is also included to coordinate outreach efforts by solar physicists for a local science festival. Each year, this festival brings in hundreds of members of the public of all ages, with exhibits designed to be informative to everyone in attendanceThis research project is aimed at characterizing the small-scale structure in density, temperature, and energy within the reconnection region, which is vital for the dynamics of reconnection and particle acceleration. If strong variations in temperature or density exist, then this will substantially impact the ionization evolution and consequently the interpretation of observations. Both two-dimensional and three-dimensional simulations will be performed, with a focus on investigating how the tearing and plasmoid instabilities drive turbulence and enhance reconnection rates. The statistical properties of the nonlinear dynamics resulting from these instabilities will be investigated to provide insight into particle acceleration and the dynamics of reconnection. While most observations of solar eruptions are interpreted under the assumption that the plasma is in ionization equilibrium, the time scales for ionization and recombination are often comparable to or longer than the time scales of the eruption. The observational predictions will therefore be made using time-dependent ionization modeling in the post processing, including the effects of non-thermal particle distributions.

磁重联是一个基本的物理空间等离子体过程，是太阳爆发的驱动力。 因此，详细了解磁场重联是了解地球空间天气物理过程的重要组成部分。磁场重联也控制着其他天体物理等离子体的动力学和加热。这一过程发生在比远程观测短得多的尺度上，但释放的能量和磁结构的变化具有重要的全球影响。该项目的目标是对太阳大气中的磁重联进行数值模拟，从而得出适合与太阳观测进行比较的预测。 这些结果将为重新连接的观测特征提供新的理解，并为快速重新连接和粒子加速中小尺度结构的作用提供新的理解。该项目包括重要的科学教育和公共宣传部分。提案小组的成员将指导本科生暑期实习生。还包括协调太阳物理学家为当地科学节所做的外联工作的资金。每年，这个节日都会吸引数百名各个年龄段的公众，展览旨在为每个人提供信息。这个研究项目旨在描述重连区域内密度，温度和能量的小尺度结构，这对重连和粒子加速的动力学至关重要。如果温度或密度存在强烈的变化，那么这将极大地影响电离演化，从而影响观测结果的解释。将进行二维和三维模拟，重点是研究撕裂和等离子体团不稳定性如何驱动湍流并提高重联率。这些不稳定性导致的非线性动力学的统计特性将被调查，以提供洞察粒子加速和动力学的重联。虽然大多数对太阳爆发的观测都是在假设等离子体处于电离平衡的情况下进行解释的，但电离和复合的时间尺度往往与爆发的时间尺度相当或更长。因此，观测预测将在后处理中使用随时间变化的电离模型，包括非热粒子分布的影响。