CAREER: Kinetic Theory of Irreversible Processes

该奖项部分由2021年美国救援计划法案（公法117-2）资助。该职业奖支持将理论、数值模拟和航天器数据分析结合起来，以推进我们对基本等离子体过程的理解。等离子体是由带电粒子组成的气体，在我们的宇宙中无处不在。霓虹灯、闪电、极光、恒星和行星际空间都是等离子态物质的例子。电磁相互作用在等离子体动力学中起着至关重要的作用，包括等离子体的通电和加热。例如，这种相互作用使太阳外层大气，即日冕加热到超过100万度的温度。太阳不断向行星际空间发射的等离子体风，即太阳风，也被加热到比目前理论预测的温度更高的温度。等离子体物理学中一个悬而未决的问题是，储存在电场和磁场中的能量如何最终加热等离子体。这一问题将在该奖项的支持下进行研究，通过开发尖端的数值工具，并辅以对过去和当前空间任务数据的理论和分析。这项研究将与一项增强的空间物理教育计划相结合，该计划将针对STEM学科中各级教育中代表性不足的少数群体。将通过夏令营和展示课程组织引人入胜的活动，以提高学生对空间物理学及其对生活和技术的影响的认识。该奖项建立了一个研究项目，旨在解决大尺度湍流系统（如日球层的天然等离子体）中动力学效应和动力学之间的相互作用。在自然界和实验室中遇到的大多数等离子体环境可以归类为弱碰撞或无碰撞，因为与碰撞弛豫相关的时间尺度比典型的动力学时间尺度长几个数量级。因此，等离子体通常远离热力学平衡，基于这种状态的弱扰动的输运模型不适用。相反，波粒相互作用等动力学机制在能量耗散和等离子体充能过程中起着至关重要的作用。该奖项支持的研究工作旨在了解动力学物理学和大尺度动力学之间的双向反馈，以推进对弱碰撞磁化等离子体中控制湍流级联、耗散和粒子能量的过程的认识。为此，将开发一个扩展的混合碰撞动力学模型，并首次用于研究弱碰撞磁化等离子体中的湍流。将对过去和当前空间任务的现场航天器数据分析进行分析，并与数值和理论结果进行比较。这项工作的结果将在日球层环境中得到应用，但也会在更奇特的天体物理系统中得到应用，比如恒星和脉冲星风，围绕着不同中心物体的吸积盘，以及星际介质。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 award is funded in part under the American Rescue Plan Act of 2021 (Public Law 117-2). This CAREER award supports bringing together theory, numerical simulations and spacecraft data analysis to advance our understanding of fundamental plasma processes. Plasmas are gases made of electrically charged particles, and they can be found everywhere in our universe. Neon lights, lightning, auroras, stars and the interplanetary space are all examples of matter in the plasma state. Electromagnetic interactions play a crucial role in the dynamics of plasmas, including plasma energization and heating. For example, such interactions are responsible for heating the outer solar atmosphere, the solar corona, to temperatures in excess of one million degrees. The wind of plasma continuously emitted by the sun into the interplanetary space, the solar wind, is also heated to temperatures higher than what current theories predict. One of the open questions in plasma physics is how the energy stored in the electric and magnetic fields can ultimately heat a plasma. This problem will be investigated with the support of this award by developing cutting-edge numerical tools complemented by theory and analysis of data from past and current space missions. The research will be integrated with an enhanced space physics education plan that will target underrepresented minority groups in STEM disciplines at all levels of education. Engaging activities will be organized through summer camps and showcase lessons to enhance student awareness about space physics and its impacts on life and technology.This award establishes a research program that addresses the interplay between kinetic effects and the dynamics on the large scales in turbulent systems such as the natural plasmas of the heliosphere. Most of the plasma environments encountered in nature and in the laboratory may be classified as weakly collisional or collisionless, in the sense that the timescales associated with collisional relaxation are orders of magnitude longer than the typical dynamical ones. As a consequence, plasmas are most often far from thermodynamic equilibrium, and transport models based on weak perturbations from such states do not apply. Instead, kinetic mechanisms such as wave particle interactions play a crucial role in the processes of energy dissipation and plasma energization. The research effort supported with this award aims to understand the two-way feedback between kinetic physics and large-scale dynamics to advance knowledge of the processes that govern the turbulent cascade, dissipation and particle energization in weakly collisional magnetized plasmas. To this end, an extended hybrid collisional kinetic model will be developed and used to investigate, for the first time, turbulence in weakly collisional magnetized plasmas. In-situ spacecraft data analysis from past and current space missions will be analyzed and compared with numerical and theoretical results. Results from this work will find application in heliospheric environments, but also in more exotic astrophysical systems such as stellar and pulsar winds, accretion disks around widely different central objects, and the interstellar medium.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.