Collaborative Research: GEM--Transition from Ion-Coupled to Electron-Only Reconnection

磁重联在太阳风磁场到地球磁场的能量传输中起着重要的作用。这一过程通过亚暴和磁鞘驱动磁尾中的全球能量释放。这个项目研究了磁鞘中的重联是如何发生的，重点是离子耦合重联和纯电子重联的相对贡献。了解磁重联对与卫星有关的国家安全优先事项具有重要意义，因为这些事件会产生空间天气影响，可能会损坏或摧毁这些系统。此外，该项目将通过培训一名博士后和一名研究生，并为高危少数民族高中生提供实习机会，支持下一代STEM科学家。该项目是对从离子耦合磁重联向纯电子磁重联过渡的关键控制因素和能量释放特性的系统研究。主要的次要问题是：(1)控制从离子耦合到纯电子重新连接的因素是什么？(2)在离子耦合很少或没有离子耦合的情况下，控制重新连接过程中加热的因素是什么？以及(3)3D物理是否影响从离子耦合到纯电子重新连接的转变？细胞内粒子动力学模拟将在2-1/2和3维进行。离子耦合程度、离子排出速度、电子排出速度和排气中的加热将被确定，并与流入条件进行比较，以确定关键的控制因素，并最终创建所有物理模型。这些模拟和模型将与MMS卫星对湍流磁鞘中重新连接的观测进行比较，以验证模型并找到观测中离子耦合程度的线索。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Magnetic reconnection plays a fundamental role in energy transport from the solar wind magnetic fields to the Earth’s magnetic field. This process drives global energy releases in the magnetotail through sub-storms and in the magnetosheath. This project studies how reconnection in the magnetosheath occurs, focusing on the relative contributions from ion-coupled and electron-only reconnection. Understanding of magnetic reconnection is important to national security priorities related to satellites as these events produce space weather affects that can damage or destroy these systems. Additionally, the project will support the next generation of STEM scientists through training of a post-doc and a graduate student and providing internships for at-risk minority high school students.This project is a systematic study of key controlling factors and energy release properties of the transition from ion-coupled to electron-only magnetic reconnection. The primary sub-questions are: (1) What are the factors controlling the transition from ion-coupled to electron-only reconnection? (2) What are the factors controlling heating during reconnection with little or no ion coupling? And (3) Does 3D physics impact the transition from ion-coupled to electron-only reconnection? Kinetic particle-in-cell simulations will be conducted in 2-1/2 and 3 dimensions. The degree of ion coupling, ion exhaust velocities, electron exhaust velocities, and heating in the exhaust will be determined and compared with inflow conditions to determine the key controlling factors and ultimately all the creation of physical models. The simulations and models will be compared with MMS satellite observations of reconnection in the turbulent magnetosheath to both validate the models and find clues to the degree of ion coupling in the observations.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.