Collaborative Research: Integration of Extended Magnetohydrodynamic (MHD) and Kinetic Effects in Global Magnetosphere Models

这笔赠款是为2012年NASA-NSF空间天气建模合作伙伴关系下选定和资助的一个项目提供部分支持。这是一项合作努力，由普林斯顿大学领导，新汉普郡大学、加州大学圣地亚哥分校、美国宇航局戈达德太空飞行中心和洛斯阿拉莫斯国家实验室也参与其中。其目标是进行一项相当于理论和计算方面的重大挑战，即开发一个最先进的全球磁层模型，该模型超越电阻MHD模型的标准框架，包括多流体物理，包括广义欧姆定律、纳入动力学效应的电子和离子的增强状态方程以及多带电粒子物种。为此，该项目将吸收和代表过去近15年来在全球磁层代码OpenGGCM的框架内对重联、电流片的不稳定性、多种流体和无碰撞等离子体中的湍流的理解所取得的许多显著进展，OpenGGCM是目前在社区中广泛使用的传统版本。团队成员中存在一套成熟的基于物理的模块，这些模块基于高伦德奎斯特数MHD、霍尔MHD、混合、多物种和完全动力学的胞内粒子-粒子程序，并将被汇集在一起，以产生一个全面的下一代全球磁层程序，其中将首次包括扩展的MHD和动力学效应。完成后，所产生的增强型全球磁层模型将交付给社区协调建模中心，以便与科学界轻松全面接触，并最终过渡到用于业务空间天气预报。这将使人们能够准确模拟造成对人类社会有直接影响的极端空间天气事件的动力学尺度过程(例如，磁重联)。虽然这一应用是针对地球磁层的，但该模型的核心科学模块具有更广泛的适用性，并可能对我们理解和预测日光层中广泛的空间天气现象的能力产生革命性的影响，这些现象涉及磁场重联、电流片不稳定性和湍流。该团队是学术界和国家实验室之间的合作伙伴关系，由几名初级科学家、博士后研究员和研究生组成，他们将接受这一广泛交叉学科的教育，涉及理论和实验空间等离子体物理、应用数学和高性能计算。

This grant is for partial support of a project selected and funded under the 2012 NASA-NSF partnership for Space Weather Modeling Collaborations. It is a collaborative effort, led by Princeton University and with participation also from University of New Hampshire, University of California-San Diego, NASA Goddard Space Flight Center, and Los Alamos National Laboratory. The objective is to undertake what amounts to a theoretical and computational grand challenge, namely to develop a state-of-the-art global magnetosphere model that goes beyond the standard framework of the resistive MHD model to include multi-fluid physics, including a generalized Ohms' law, enhanced equations of state for electrons and ions that incorporate kinetic effects, and multiple charged particle species. To this end, the project will assimilate and represent many of the remarkable advances made over the last almost 15 years in our understanding of reconnection, instabilities of current sheets, multiple fluids, and turbulence in collisionless plasmas within the framework of a global magnetosphere code, the OpenGGCM, a traditional version of which is presently used extensively in the community. A suite of mature physics-based modules, based on high-Lundquist-number MHD, Hall MHD, hybrid, multi species, and fully kinetic particle-in-cell codes exist amongst the team members and will be brought together to produce a comprehensive, next-generation global magnetosphere code that will include for the first time extended MHD and kinetic effects. When completed, the resulting enhanced global magnetosphere model will be delivered to the Community Coordinated Modeling Center (CCMC) for easy and full access to the scientific community and eventual transition to use for operational space weather forecasting. This will enable the accurate modeling of the kinetic scale processes (e.g., magnetic reconnection) responsible for extreme space weather events with direct impact on human society. While the application is geared to the Earth's magnetosphere, the core science module of the model has much broader applicability, and has potentially transformative implications for our ability to understand and predict a broad range of space weather phenomena in the heliosphere that involve magnetic reconnection, instabilities of current sheets, and turbulence. The team, which is a partnership between academia and national laboratories, consists of several junior scientists, postdoctoral fellows, and graduate students who will be educated in this broadly interdisciplinary subject, involving theoretical as well as experimental space plasma physics, applied mathematics, and high-performance computing.