Particle Acceleration During Collisionless Magnetic Reconnection

本项目致力于对磁重联过程中粒子加速的理解。磁重联是一个基本的过程，在这个过程中，磁能被转化为高速流动和高能粒子。它是自然界重要现象的基础，包括太阳耀斑、地球磁场的强烈扰动以及实验室聚变实验的中断。磁重联也是空间天气的驱动因素，这可能会对卫星通信产生负面影响，并威胁到太空中的宇航员。在理解磁重联过程中在自然界和实验室中看到的快速释放磁能的机制方面，已经取得了很大的进展。太阳观测表明，释放的磁能中有很大一部分以高能粒子的形式出现。粒子加速的机制还不清楚，这是本研究项目的重点。该项目将包括本科生的积极参与，包括女研究生在内的研究生的培训，从而促进国家自然科学基金会的广泛教育目标。该研究计划的技术目标是了解磁重联过程中电子和离子的加热和加速，并开发一个可以与观测相比较的粒子加速模型。将利用粒子单元模拟和分析方法解决与磁重联过程中电子和离子加速有关的四个关键问题：确定和量化电子加速的主要机制；为普遍观测高能粒子的幂函数谱奠定物理学基础；建立脉冲耀斑中离子加速和丰度增强的机制；以及开发可用于预测与空间天气有关的危险的粒子加速福克-普朗克模型。将继续与从事实验室实验的科学家合作，并利用卫星数据将理论预测与观测结果进行基准比较。

This project is focused on the understanding of particle acceleration during the process of magnetic reconnection. Magnetic reconnection is a fundamental process in which magnetic energy is converted into high-speed flows and energetic particles. It underlies important phenomena in nature, including solar flares, strong disturbances in the Earth's magnetic field, and disruptions in laboratory fusion experiments. Magnetic reconnection is also the driver of space weather, which can negatively impact satellite communications and threaten astronauts in space. Great progress has been made on understanding the mechanisms for the fast release of magnetic energy seen in nature and the laboratory during magnetic reconnection. Solar observations suggest that a large fraction of the magnetic energy released appears in the form of energetic particles. The mechanisms for particle acceleration are not understood and are the focus of this research project. The project will include active involvement of undergraduate students, the training of graduate students, including female graduate students, and thus further the broad educational goals of NSF.The technical goal of this research program is to understand electron and ion heating and acceleration during magnetic reconnection and to develop a model for particle acceleration that can be compared with observations. Particle-in-cell simulations and analytic approaches will be used to address four key issues related to electron and ion acceleration during magnetic reconnection: to identify and quantify the dominant mechanisms for electron acceleration; to establish the physics basis for the ubiquitous observations of power-law spectra of energetic particles; to establish the mechanism for ion acceleration and abundance enhancements in impulsive flares; and to develop a Fokker-Planck model of particle acceleration that can be used to predict the hazards associated with space weather. Collaborations will be continued with scientists working on laboratory experiments and with satellite data to benchmark the theoretical predictions with observations.