CAREER: Furthering Our Understanding of Fast Magnetic Reconnection in the Geospace Environment — from Electron-only Reconnection to Turbulent Reconnection

磁重联是地球空间等离子体中最重要的能量转换和传输过程之一。一个重要的基本问题是，磁重联发生的速度有多快，从而导致自然界中磁能的爆炸性释放。这个项目将通过数值模拟来解决这个重要的基本问题。教育部分是科学与艺术的独特结合。PI将与达特茅斯学院数字艺术领导与创新实验室的本科生动画师合作，制作高质量的动画，提高下一代STEM劳动力对空间等离子体物理的认识和可及性。一个新的理论框架，包括超相对论效应、不对称、背压和压力各向异性，将用于测试新观察到的磁重联类型。其中包括首次在弓形激波下游的磁鞘中发现的纯电子重联，以及在磁尾中捕获的无碰撞湍流重联。该项目将使用单元内粒子代码VPIC，辅以磁流体动力学（MHD）代码Athena/Athena++和Hall-MHD代码F3D来(1)解释和预测观察到的仅电子重联的快速速率，(2)解释和预测无碰撞湍流重联的快速速率。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。

Magnetic reconnection is one of the most important energy conversion and transport processes in geospace plasmas. One important fundamental question is how fast magnetic reconnection occurs, causing an explosive release of magnetic energy in nature. This project will address this important fundamental question through numerical simulations. The educational component is a unique combination of Science and Art. The PI will work with undergraduate student animators at the Digital Arts Leadership and Innovation Lab of Dartmouth College to produce high-quality animations that elevate the awareness and accessibility of space plasma physics to the next generation of the STEM workforce. A novel theoretical framework that includes ultra-relativistic effects, asymmetry, back-pressure and pressure anisotropy will be used to test against newly observed types of magnetic reconnection. These include electron-only reconnection first found in the magnetosheath downstream of the bow shock and collisionless turbulent reconnection captured in the magnetotail. The project will use the particle-in-cell code VPIC, complemented with the magnetohydrodynamic (MHD) code Athena/Athena++ and the Hall-MHD code F3D to (1) explain and predict the observed fast rate of electron-only reconnection and (2) explain and predict the fast rate of collisionless turbulent 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.