Exploration of the Nonequilibrium Statistical Mechanics of Turbulent Collisionless Plasmas

这个项目将使用新的统计力学方法来探索湍流等离子体。统计力学是物理学的一个核心分支，在描述诸如气体、液体和量子场等物质的物理特性方面取得了巨大成功。然而，将其原理扩展到描述存在于整个宇宙中的热的脆弱等离子体，包括太阳风、星际介质和黑洞周围的物质，一直是一个挑战。该项目将使用计算机模拟和新的数学方法来探索湍流等离子体的统计力学。结果将提高预测天体物理、空间和实验室系统中等离子体多尺度行为的能力，包括潜在的未来聚变能反应堆。这些方法将用于模拟高能粒子和等离子体产生的辐射的发生，并与观测结果进行比较。该项目将吸引研究生，并包括公众宣传和本科生指导计划。本项目从非平衡统计力学的角度考虑无碰撞等离子体湍流的耗散。它将涉及应用新的理论方法来量化非平衡系统中的不可逆能量耗散。该团队将执行和分析不同物理状态下等离子体湍流的动力学和混合动力学模拟，包括相对论和非相对论情况，以确定(1)湍流中熵产率的统计分布，以及(2)湍流能量耗散是否导致可以分析建模的广义最大熵状态。结果将提高对无碰撞等离子体中湍流能量耗散的理解，从而导致非热粒子加速和随后的辐射发射的新模型。这项工作可以直接应用于广泛的空间和天体物理系统，包括太阳风和黑洞吸积流。除此之外，它还将导致与其他耗散等离子体过程相关的见解，例如磁重联和冲击，以及一般的非平衡统计系统。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。

This project will explore turbulent plasmas using novel statistical mechanics methods. Statistical mechanics is a core branch of physics that has been enormously successful in describing the physical characteristics of matter such as gases, liquids, and quantum fields. However, it has been challenging to extend its principles to describe hot tenuous plasmas that exist throughout the Universe, including the solar wind, the interstellar medium, and matter around black holes. This project will use computer simulations and new mathematical methods to explore the statistical mechanics of turbulent plasmas. The result will be an improved capability to predict the multiscale behavior of plasmas in astrophysical, space, and laboratory systems, including potential future fusion energy reactors. The methods will be used to model the occurrence of high-energy particles and radiation produced by the plasma, which can be compared to observations. The project will engage graduate students and include public outreach and undergraduate mentoring programs.The project considers the dissipation of collisionless plasma turbulence from the perspective of nonequilibrium statistical mechanics. It will involve the application of new theoretical approaches for quantifying irreversible energy dissipation in nonequilibrium systems. The team will perform and analyze kinetic and hybrid-kinetic simulations of plasma turbulence in different physical regimes, including relativistic and non-relativistic cases, to determine (1) the statistical distribution of entropy production rates in turbulence, and (2) whether turbulent energy dissipation leads to generalized maximum entropy states that can be modeled analytically. The outcome will be an improved understanding of turbulent energy dissipation in collisionless plasmas, leading to new models of nonthermal particle acceleration and subsequent radiation emission. The work has direct applications to a broad range of space and astrophysical systems, including the solar wind and black-hole accretion flows. Beyond this, it will lead to insights relevant to other dissipative plasma processes, such as magnetic reconnection and shocks, and nonequilibrium statistical systems in general.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.