WoU-MMA Collaborative Research: Turbulence and Reconnection in Magnetically-Dominated Astrophysical Plasmas

在许多天体物理物体中，比如磁场气泡和由快速旋转的中子星（称为脉冲星风星云）提供动力的高能粒子，磁场控制着带电粒子热气体的整体动力学，带电粒子是围绕物体的相对论性天体物理等离子体。在这样的天体物理对象中，通过磁重联的磁能耗散——磁场线湮灭的过程，将它们的能量释放给粒子——可能为观测到的高能电磁和粒子发射提供动力。最近的一些观测，如Fermi和AGILE卫星探测到的蟹状星云伽玛射线耀斑，都强调了磁重联对天体物理高能源中发射粒子加速的关键作用。这项工作将包括针对本科生的项目，结果将通过专门的讲习班传播给高中生。一项名为“天文汤”（Astro-soup）的新项目将被实施，在为纽约市无家可归的人提供食物的同时，还将讨论与这项工作相关的天体物理学主题。本研究的总体目标是解释蟹状星云中令人费解的非热发射现象，蟹状星云是脉冲星风星云的原型，也是高能天体物理学中最著名的源。它的燃烧和静止特征将被建模，从无线电到高能伽马射线，在一个基于相对论磁重联的单一物理场景中。研究的每个阶段都将结合分析方法和大规模的第一性原理细胞内粒子模拟。从第一性原理出发，研究蟹状星云中发生的大规模流动如何自一致地产生重联层，以及重联和流体运动如何相互作用自然地导致有效的粒子加速，将为天体物理高能源的重联模型奠定坚实的基础。这些结果也将与其他耀斑源相关，比如来自超大质量黑洞的喷流，在那里伽马射线耀斑最近被探测到与中微子相对应，从而解决了美国国家科学基金会“宇宙之窗：多信使天体物理学时代”的目标。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。

In many astrophysical objects -- like bubbles of magnetic fields and high-energy particles powered by rapidly spinning neutron stars called pulsar wind nebulae -- magnetic fields control the overall dynamics of the hot gas of charged particles, the relativistic astrophysical plasma surrounding the object. In such astrophysical objects dissipation of magnetic energy via magnetic reconnection -- a process where magnetic field lines annihilate, releasing their energy to the particles -- may power the observed high-energy electromagnetic and particle emission. A number of recent observations such as the Crab Nebula gamma-ray flares detected by Fermi and AGILE satellites have emphasized the critical role of magnetic reconnection for the acceleration of the emitting particles in astrophysical high-energy sources. This work will include projects for undergraduate students, and the results will be disseminated to high-school students through dedicated workshops. A new program, "Astro-soup," will be implemented, where serving food to homeless people in New York City will be accompanied by discussion on astrophysical topics of relevance for this work. The overall goal of this research is to explain the puzzling phenomenology of non-thermal emission in the Crab Nebula, the prototype of pulsar wind nebulae and the most famous source in high-energy astrophysics. Its flaring and quiescent signatures will be modeled, from radio to high-energy gamma-rays, in a single physically-grounded scenario based on relativistic magnetic reconnection. Every stage of the research will combine analytical approaches with large-scale first-principles particle-in-cell simulations. The reconnection model of astrophysical high-energy sources will be placed on solid footing by studying from first principles how reconnection layers are self-consistently generated by large-scale flows occurring in the Crab Nebula and how the interplay of reconnection and fluid motions can naturally lead to efficient particle acceleration. The results will also be relevant for other flaring sources, like jets from supermassive black holes, where gamma-ray flares have recently been detected together with neutrino counterparts, thus addressing the goals of NSF's "Windows on the Universe: The Era of Multi-Messenger Astrophysics" Big Idea.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.