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.

磁重新连接是一种基本的物理空间等离子体过程，是太阳喷发的驱动力。 因此，对磁重新连接的详细理解是了解负责地球空间天气的物理过程的重要组成部分。磁重新连接也控制其他天体物理等离子体的动力学和加热。该过程的长度比远程观察到的时间短得多，但是释放的能量和磁性结构的变化具有重要的全球后果。该项目的目的是对太阳大气中的磁重新连接进行数值模拟，从而导致适合与太阳观测比较的预测。 结果将提供对重新连接的观察性特征的新理解，以及对小规模结构在快速重新连接和粒子加速度中的作用的新理解。该项目包括大量的科学教育和公共外展成分。提案团队的成员将指导本科暑期实习生。还包括资金来协调太阳能物理学家在当地科学节上的宣传工作。每年，这个节日都会吸引数百名所有年龄段的公众成员，旨在为参加研究项目的每个人提供信息，旨在表征重新连接区域内密度，温度和能源的小规模结构，这对于重新连接和粒子加速的动态至关重要。如果存在强烈的温度或密度变化，则将大大影响电离演化，从而对观测值进行解释。将进行二维和三维模拟，重点是研究撕裂和浆液不稳定性如何驱动湍流并提高重新连接率。将研究由这些不稳定性产生的非线性动力学的统计特性，以洞悉粒子加速度和重新连接的动力学。虽然大多数太阳喷发的观察结果是在血浆处于电离平衡的假设下解释的，但电离和重组的时间尺度通常与喷发的时间尺度相当或更长。因此，观察性预测将使用后处理中的时间依赖性电离建模进行，包括非热粒子分布的影响。