Collaborative Research: Energy Conversion Beyond the First Law of Thermodynamics in Non-Equilibrium Plasmas

该奖项支持西弗吉尼亚大学和新汉普郡大学研究弱碰撞等离子体中的能量转换的合作努力。等离子体研究中最具挑战性的问题之一是理解能量是如何在电磁场和等离子体热能之间转换的，等离子体热能是与带电粒子的随机运动有关的能量。等离子体是温度足够高的气体，以至于电子从原子中分离出来。这是许多类型的等离子体的一个重要问题，包括太空中的等离子体和用于聚变能源开发的非常热的等离子体。这些等离子体，其中粒子之间的碰撞非常罕见，通常远离局部热力学平衡(LTE)，这意味着人们甚至无法定义传统意义上的温度。该项目以量化非LTE等离子体中能量转换的最新结果为基础，首次系统研究了弱碰撞等离子体中的非LTE能量转换。该项目将使用最先进的粒子在单元(PIC)模拟和来自磁层多尺度(MMS)任务的卫星数据。二维磁重联和湍流的参数模拟将被用来理解热能转换对环境等离子体参数的依赖。二次岛和磁通量绳将在二维和三维磁重联中被研究，因为它们是已知的粒子加速和非LTE动力学位置。最后，将理论形式推广到考虑随机运动和整体运动中的能量，并将其用于研究二维重联和湍流中的能量转换。该项目将直接促进研究太阳大气中爆发耀斑的能量转换、产生极光和空间天气影响的地磁亚暴以及太阳风的加热；它还将为应用于等离子体科学的其他领域，包括高能量密度和聚变等离子体奠定基础。该合作奖由物理学部的等离子体物理项目和大气和地球空间科学部的磁层物理项目共同资助。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。

This award supports a collaborative effort at West Virginia University and the University of New Hampshire to study energy conversion in weakly collisional plasmas. One of the most challenging problems in the study of plasmas - gases hot enough that electrons come apart from the atoms - is understanding how energy is converted between electromagnetic fields and the thermal energy of the plasma, which is the energy associated with random motion of the electrically charged particles. This is an important problem across many types of plasmas, including plasmas in space and the very hot plasmas that are used in fusion energy development. These plasmas, where collisions between particles are very rare, are most often far from local thermodynamic equilibrium (LTE), which means that one cannot even define a temperature in the traditional sense. This project builds on a recent result quantifying energy conversion in non-LTE plasmas to perform the first systematic study of the non-LTE energy conversion in weakly collisional plasmas.The project will employ state-of-the-art particle-in-cell (PIC) simulations and satellite data from the Magnetospheric Multiscale (MMS) mission. Parametric simulations of two-dimensional magnetic reconnection and turbulence will be used to understand the dependence of thermal energy conversion on ambient plasma parameters. Secondary islands and flux ropes will be studied in two-dimensional and three-dimensional magnetic reconnection since they are known to be sites of particle acceleration and non-LTE dynamics. Finally, the theoretical formalism will be generalized to account for energy in both random motion and bulk motion and it will be used to study energy conversion in two-dimensional reconnection and turbulence. The project will directly contribute to the study of energy conversion in eruptive flares in the solar atmosphere, geomagnetic substorms that produce aurora and space weather impacts, and the heating of the solar wind; it will also set the stage for application in other areas of plasma science, including high energy density and fusion plasmas. The collaborative award is co-funded by the Plasma Physics program in the Division of Physics and the Magnetospheric Physics program in the Division of Atmospheric and Geospace Sciences.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.