Local physics control of the x-line orientation in three-dimensional asymmetric magnetic reconnection

三维不对称磁重联中x线方向的局部物理控制

• 批准号: 1757599
• 负责人: Yi-Hsin Liu
• 金额: $ 0.63万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1757599&HistoricalAwards=false
• 关键词: Local; physics; control; line; orientation

Magnetic reconnection is arguably one of the most important energy conversion and transport processes in space plasmas. This project aims to answer a fundamental question related to our understanding of magnetic reconnection: is there a simple principle that determines the orientation of the reconnection x-line in a asymmetric current sheet? The solution of this basic question remains unclear with our current understanding of magnetic reconnection, and the project aims to use Blue Waters to resolve this issue. Ultimately, the project's goal is to develop an understanding of the three-dimensional (3D) nature of asymmetric magnetic reconnection itself, which is an important step in the quest for predicting the location and orientation of magnetic reconnection in the Earth's magnetopause. Moreover, increased understanding of x-line will enable space scientists to more accurately estimate the efficiency of flux transfer from solar wind to the Earth's magnetosphere. In addition, the work proposed here is timely to the study of dayside reconnection during the 1st phase of NASA's Magnetospheric Multiscale Mission (MMS). The goal of the project centers around the local physics control of 3D x-line in asymmetric reconnection, which has a direct application to terrestrial magnetopause. The project will address the following questions: a) What is the underlying physics that control the 3D x-line orientation? b) How does the 3D x-line spread? Does it have an intrinsic extent? c) How does the diamagnetic drift affect the orientation and the motion of a 3D x-line? d) What role do oblique tearing instabilities and the resulting flux ropes play?The development of reconnection x-line requires a fully kinetic description, hence this project will employ the particle-in-cell (PIC) code, VPIC, which is optimized on the Blue Waters supercomputer. For 3D simulations, the project employs an innovative approach to induce a single x-line by using a localized perturbation so that the x-line has sufficient freedom to choose its orientation.

磁重新连接可以说是空间等离子体中最重要的能量转换和传输过程之一。 该项目旨在回答与我们对磁重新连接的理解有关的基本问题：是否有一个简单的原则决定了不对称电流表中重新连接X线的方向？ 我们目前对磁重新连接的理解尚不清楚这个基本问题的解决方案，该项目旨在使用蓝色水来解决此问题。最终，该项目的目标是建立对不对称磁重新连接本身的三维（3D）性质的理解，这是寻求预测地球磁磁性中磁重新连接位置和方向的重要一步。 此外，对X线的了解增加将使太空科学家更准确地估计从太阳风到地球磁层的通量转移的效率。此外，此处提出的工作及时研究了NASA磁层多尺度任务（MMS）的第一阶段重新连接的研究。该项目的目的围绕着不对称重新连接中3D X线的本地物理控制，该控制直接应用于陆生磁磁磁；该项目将解决以下问题：a）控制3D X线方向的基础物理学是什么？ b）3D X线如何扩散？它具有内在范围吗？ c）直流漂移如何影响3D X线的方向和运动？ d）倾斜撕裂不稳定性和由此产生的磁通绳的扮演的角色？重新连接X线需要完全动力学描述，因此，该项目将采用粒子中的粒子（PIC）代码，VPIC，该代码已对此进行了优化蓝色水域超级计算机。对于3D模拟，该项目采用创新方法来通过使用局部扰动来诱导单个X线，从而使X线具有足够的自由来选择其方向。

项目成果

Drift turbulence, particle transport, and anomalous dissipation at the reconnecting magnetopause

• DOI: 10.1063/1.5027086
• 发表时间: 2018-06-01
• 期刊: PHYSICS OF PLASMAS
• 影响因子: 2.2
• 作者: Le, A.;Daughton, W.;Bird, R.
• 通讯作者: Bird, R.

Orientation and Stability of Asymmetric Magnetic Reconnection X Line

• DOI: 10.1029/2018ja025410
• 发表时间: 2018-05
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: Yi‐Hsin Liu;Michael Hesse;Tak Chu Li;M. Kuznetsova;Ari Le