Relativistic Asymmetric Magnetic Reconnection: Theory and Kinetic Modeling

本项目将探索磁化天体物理等离子体中的磁重联过程。大多数空间和天体物理系统，包括太阳和银河系内外的恒星，都是由热的电离气体组成的——一种被磁场渗透的等离子体。通常，这些系统通过磁重联过程迅速产生高能光和粒子。这个项目将利用计算机模拟和包括由天体物理观测引起的更现实的条件，来改进对磁重联及其产生的辐射的理解。模拟将用于将等离子体的条件与辐射的特性联系起来。这项研究工作将提高我们对天体物理等离子体行为的理解，以及来自银河系内外的高能辐射的来源。该项目由物理部、天文科学部和促进竞争性研究的既定计划（EPSCoR）共同资助。在相对论和非对称极限条件下，研究了磁重联的基本等离子体过程，在这些条件下，每个粒子的磁能大于静止质能，相互作用的磁结构的等离子体性质彼此不同。该项目将尝试实现三个关键目标：(1)发展相对论性、不对称磁重联的尺度预测；(2)确定初始不对称等离子体参数与重联产生的高能非热粒子分布之间的关系；(3)探讨磁重联对全球天体物理系统中非热粒子分布的贡献。前两个目标将通过对磁重联的等离子体模拟进行调查来实现，并将其与推导出的理论预测进行分析和比较。第三个目标将通过研究活动星系核的相对论喷流模拟来估计重联产生的高能粒子的非热谱来实现。待探索的参数体系及其在相对论性喷流中的应用与等离子体天体物理学领域的发展直接相关，可以为天体物理学中加速高能粒子和相关脉冲发射的起源提供见解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will explore the process of magnetic reconnection in magnetized astrophysical plasmas. Most space and astrophysical systems, including the sun and stars in and out of the milky way, are made up of hot, ionized gas -- a plasma permeated by magnetic fields. Frequently, high energy light and particles are rapidly generated by these systems through a process known as magnetic reconnection. An improved understanding of magnetic reconnection and the radiation it generates will be developed by this project using computer simulations and by including more realistic conditions motivated by astrophysical observations. The simulations will be used to connect the conditions of the plasma to the characteristics of the radiation. The research effort will improve our understanding of how astrophysical plasmas behave and what are the sources of high energy radiation from our galaxy and beyond. This project is jointly funded by the Division of Physics, the Division of Astronomical Sciences, and the Established Program to Stimulate Competitive Research (EPSCoR).The fundamental plasma process of magnetic reconnection will be studied in the relativistic and asymmetric limit, in regimes where the magnetic energy per particle is larger than the rest mass energy and the plasma properties of the interacting magnetic structures differ from each other. The project will attempt to achieve three key goals: (1) develop scaling predictions for relativistic, asymmetric magnetic reconnection; (2) identify relationships between the initial asymmetric plasma parameters and the energetic, non-thermal particle distributions generated by reconnection; and (3) explore the contribution of magnetic reconnection to the non-thermal particle distribution in a global astrophysical system. The first two goals will be approached by performing a survey of plasma simulations of magnetic reconnection, which will be analyzed and compared with derived theoretical predictions. The third goal will be achieved by examining relativistic jet simulations of active galactic nuclei to estimate the reconnection-generated non-thermal spectrum of energetic particles. The parameter regimes to be explored, along with the application to relativistic jets is directly relevant to the growing field of plasma astrophysics and can provide insight into the origin of accelerated high energy particles and the associated impulsive emission in astrophysics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.