The Dynamic Onset of Magnetic Reconnection

磁重联的动态开始

• 批准号: 2010136
• 负责人: Nuno Gomes Loureiro
• 金额: $ 30.24万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2010136&HistoricalAwards=false
• 关键词: Dynamic; Onset; Magnetic; Reconnection

Plasma is the most common form of matter found in the visible universe. Plasmas occurring in space and in astrophysical environments, as well as in laboratories on Earth, often carry magnetic fields. The interaction of the plasma with the magnetic field that pervades it is highly nonlinear and complex: the magnetic field affects the plasma dynamics and, conversely, the plasma can change the magnetic field. One of the most spectacular examples of such interaction is the process of magnetic reconnection: a plasma-driven reconfiguration of the magnetic field that threads it, which results in an explosive release of energy. The most popular manifestation of this phenomenon are solar flares; but reconnection occurs ubiquitously throughout the universe. The goal of this research is to advance the understanding of how the process of reconnection is triggered in a magnetized plasma; by doing so, it will contribute to the goals of NSF's "Windows on the Universe: The Era of Multi-Messenger Astrophysics" Big Idea.Magnetic reconnection is a two-step process: an initial, slow stage of energy build-up and current-sheet formation, followed by the sudden, often explosive stage of energy release. Reconnection studies largely tend to focus on the latter, driven by attempts to solve the critically important problems of reconnection rate and energy partition. In this regard, a prominent feature of the last decade of reconnection research has been the plasmoid instability, whose key role in addressing those questions is now widely appreciated. However, the existence of this, and other, current sheet instabilities implies that the onset and the energy release stages cannot be trivially decoupled, since such instabilities set specific conditions on the parameters of the current sheets that are physically realizable; for example, a system-size Sweet-Parker current sheet in large systems can never dynamically arise because a tearing instability will inevitably disrupt the forming sheet much before it attains the Sweet-Parker ratio. The aim of this research is to develop the theoretical (analytical and numerical) understanding of the conditions imposed on the energy release stage by the build-up stage, thus paving the route for self-consistent studies of magnetic reconnection.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.

等离子体是可见宇宙中最常见的物质形式。在太空和天体物理环境中以及在地球上的实验室中产生的等离子体通常带有磁场。等离子体与遍布其中的磁场的相互作用是高度非线性和复杂的：磁场影响等离子体动力学，相反，等离子体可以改变磁场。这种相互作用的最壮观的例子之一是磁重联过程：等离子体驱动的磁场重新配置，导致能量的爆炸性释放。这种现象最常见的表现是太阳耀斑；但在整个宇宙中，重新连接无处不在。这项研究的目的是促进对如何在磁化等离子体中触发重连接过程的理解；通过这样做，它将有助于实现NSF的“宇宙之窗：多信使天体物理学时代”的目标。磁重联是一个两步的过程：首先是能量积累和电流片形成的初始缓慢阶段，然后是能量释放的突然、通常是爆炸性的阶段。重连研究在很大程度上倾向于后者，试图解决重连速率和能量分配等至关重要的问题。在这方面，过去十年重联研究的一个突出特征是等离子体不稳定性，它在解决这些问题方面的关键作用现在得到了广泛的认识。然而，这种和其他电流片不稳定性的存在意味着起始阶段和能量释放阶段不能简单地解耦，因为这种不稳定性为电流片的参数设定了物理上可实现的特定条件；例如，在大型系统中，系统尺寸的Sweet-Parker电流片永远不会动态产生，因为在达到Sweet-Parker比之前，撕裂不稳定性将不可避免地破坏成形片。本研究的目的是发展理论（分析和数值）理解积聚阶段对能量释放阶段施加的条件，从而为磁重联的自一致研究铺平道路。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。

项目成果

Plasma Dynamics in Low-Electron-Beta Environments

低电子β环境中的等离子体动力学

• DOI: 10.3389/fspas.2021.621040
• 发表时间: 2021
• 期刊: Frontiers in Astronomy and Space Sciences
• 影响因子: 3
• 作者: Boldyrev, Stanislav;Loureiro, Nuno F.;Roytershteyn, Vadim
• 通讯作者: Roytershteyn, Vadim

Spectrum of kinetic-Alfvén-wave turbulence: intermittency or tearing mediation?

动力阿尔芬波湍流谱：间歇性还是撕裂中介？

• DOI: 10.1093/mnras/stad2231
• 发表时间: 2023
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Zhou, Muni;Liu, Zhuo;Loureiro, Nuno F.
• 通讯作者: Loureiro, Nuno F.

Laminar and turbulent plasmoid ejection in a laboratory Parker Spiral current sheet

• DOI: 10.1017/s0022377821000775
• 发表时间: 2021-04
• 期刊: Journal of Plasma Physics
• 影响因子: 2.5
• 作者: E. Peterson;D. Endrizzi;M. Clark;J. Egedal;K. Flanagan;N. Loureiro;J. Milhone;J. Olson;C. Sovinec;J. Wallace;C. Forest