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

磁场重联是地球空间等离子体中最重要的能量转换和输运过程之一。一个重要的基本问题是磁重联发生的速度有多快，导致自然界中磁能的爆炸性释放。该项目将通过数值模拟来解决这一重要的基本问题。PI将与达特茅斯学院数字艺术领导力和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学的认识和可访问性。一个新的理论框架，包括超相对论效应，不对称性，背压和压力各向异性将被用来测试对新观察到的类型的磁重联。其中包括在弓形激波下游的磁鞘中首次发现的仅电子重联，以及在磁尾中捕获的无碰撞湍流重联。该项目将使用粒子细胞代码VPIC，与磁流体动力学（MHD）代码Athena/Athena++和Hall-MHD代码F3 D互补，以（1）解释和预测观察到的仅电子重联的快速速率和（2）解释和预测无碰撞湍流重联的快速速率。该奖项反映了NSF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。

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.