AGS-PRF: Elucidating the Channels of Energy Transport and Particle Energization in Collisionless Plasmas

了解等离子体中无碰撞能量输运的通道是太阳物理学和天体物理学湍流界建立无碰撞等离子体湍流模型的关键一步，该模型可以根据大尺度参数观测预测粒子的能量和加速度。开发这种预测能力对于正在进行的努力至关重要，因为我们正在努力创建一个来自太阳的能量流的全球模型，通过行星际介质，并到达日球层的边界。为了清楚地了解实现这一目标所需的无碰撞能量输运渠道，本项目将协调现有的无碰撞能量输运模型，并产生一个与流体和动力学等离子体理论一致的模型。这个博士后奖学金由一位早期职业女性PI领导。更广泛的影响包括支持PI发展她的研究，推广和教学能力。近年来，人们提出了两种主要的无碰撞等离子体湍流能量输运模型：流体模型和动力学模型。用于研究这些无碰撞能量传递模型的诊断工具分别是Pi-D和场-粒子相关（FPC）技术。尽管在各自的范围内（流体理论和动力学理论）有严格的理论基础，但这两种模型似乎是不相容的，而且尚不清楚如何协调使用从它们产生的诊断技术。此外，对于这些诊断遗漏了某些可能对粒子能量（如热流或弹道粒子运动）很重要的术语的未知后果以及关于这些分析技术适用的背景（即全局与局部）的问题也提出了疑问。协调两种模型及其诊断是至关重要的，以便科学界对无碰撞能量输运过程作出明确的描述，并了解在无碰撞能量输运研究中可以使用全局和局部方法的条件。在日球层，这些知识为航天器设计和模拟开发中的资源流动提供了信息。为此，这是一个及时的研究项目，它将通过解决无碰撞等离子体湍流中两种主要能量传输模型之间的差异，(i)阐明日球层内无碰撞能量传输的通道，（ii）阐明Pi-D和FPC技术的使用，以确定这些方法在局部和全局上捕获系统动力学的效果。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。

Understanding the channels of collisionless energy transport in plasmas is a key step forward in the heliophysics and astrophysics turbulence communities’ goal of creating a model of collisionless plasma turbulence that can predict particle energization and acceleration rates based on parameter observations at large scales. Developing this predictive capability is critical to the ongoing efforts to create a global model of the flow of energy from the Sun, through the interplanetary medium, and out to the boundary of the heliosphere. To reach clear understanding of the channels of collisionless energy transport necessary for achieving this goal, this project will reconcile the existing collisionless energy transport models and produce a model that is consistent with both fluid and kinetic plasma theory. This post-doctoral fellowship is led by an early-career woman PI. The broader impacts include support for the PI in developing her research, outreach, and teaching capabilities.In recent years, two major models of energy transport in collisionless plasma turbulence have been suggested: a fluid model and a kinetic model. Diagnostic tools for studying each of these models for collisonless energy transfer are the Pi-D and field-particle correlation (FPC) technique, respectively. Despite rigorous theoretical footing within their respective limits (fluid and kinetic theory), the two models appear to be incompatible and it is not clear how the diagnostic techniques that have arisen from them may be used in concert. Furthermore, questions have been raised regarding the unknown consequences of these diagnostics omitting certain terms that may be important for particle energization (such as the heat flux or ballistic particle motion) and regarding the contexts (i.e. global vs. local) in which these analysis techniques are applicable. Reconciling the two models and their diagnostics is critical in order for the community to arrive at an unequivocal description of the process of collisionless energy transport and to understand the conditions where global and local methods can be used in the study of collisionless energy transport. In the heliosphere, this knowledge informs the flow of resources in both spacecraft design and simulation development. To this end, this is a timely research project that will, by resolving discrepancies between the two leading models of energy transport in collisionless plasma turbulence, (i) elucidate the channels of collisionless energy transport within the heliosphere, and (ii) clarify the use of Pi-D and the FPC technique to determine how well these methods capture system dynamics, both locally and globally.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.