Relaxation, Intermittency and Dissipation in a Collisionless Plasma

无碰撞等离子体中的弛豫、间歇和耗散

• 批准号: 2108834
• 负责人: William Matthaeus
• 金额: $ 48万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2108834&HistoricalAwards=false
• 关键词: Relaxation; Intermittency; Dissipation; Collisionless; Plasma

The purpose of this project is to improve understanding of the basic science of turbulence in a plasma. Turbulence is the complex dynamics of a fluid or gas resulting from nonlinear forces that span a wide range of scales in space and time. Many important effects emerge from turbulence, such as mixing and rapid transport of heat and energy; this influences terrestrial fluids as well as electrically conducting gases, or plasmas, in space and on the sun. Turbulence is usually not uniform in space – it tends to quickly self-organize into irregularly shaped "cells." Inside these cells the plasma is typically quiescent, but the thin boundaries between cells are highly active with sometimes explosive results. Processes causing this self-organization and formation of the cell boundaries are studied in this project. This effort will support a post-doctoral researcher and advance understanding of many observed space plasma phenomena, including solar flares and variability of turbulence in the solar wind, thus contributing to the science underlying space weather.Relaxation processes, turbulence cascade and dissipation mechanisms are each an important area of study in plasma physics and its applications. However these are most frequently studied separately. The fundamental hypothesis advanced in this project is that the nature of the intermittent cascade, and the dissipation that it leads to, are strongly influenced by specific relaxation processes that originate at the energy containing scales. In particular, local relaxation leads to spatial cellularization, and the associated spatial nonuniformity controls the formation of coherent structures, where dissipation is expected to be greatly enhanced. This has been studied, although incompletely, in fluid plasma models such as magnetohydrodynamics, but is poorly understood in fully kinetic plasma models to be considered within this project. Establishing such fundamental connections as parameters are changed to vary among modes of relaxation will advance understanding of fundamental plasma physics.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.

该项目的目的是提高对等离子体湍流基础科学的理解。湍流是由非线性力跨越空间和时间范围范围范围广泛的流体或气体的复杂动力学。湍流中出现了许多重要的影响，例如混合和热能的快速运输；这会影响陆地流体以及在太空中和太阳下进行电气或等离子体的导电或等离子体。湍流通常在空间中不统一 - 它往往会迅速自组织成不规则形状的“细胞”。在这些细胞内部，血浆通常是静止的，但是细胞之间的薄边界有时具有爆炸性的结果。在该项目中研究了导致这种自我组织和细胞边界形成的过程。这项工作将支持博士后研究人员，并提高对许多观察到的空间等离子体现象的了解，包括太阳耀斑和太阳风中湍流的可变性，从而有助于延期太空的科学。递延过程，湍流级联和耗散机制是血浆物理学及其应用的重要领域。但是，这些是最常研究的。该项目中提出的基本假设是间歇性级联的性质及其导致的耗散性的性质受到源自包含量表能量的特定放松过程的强烈影响。特别是，局部弛豫会导致空间细胞化，相关的空间不均匀性控制着相干结构的形成，其中预计耗散会大大增强。在流体血浆模型（例如磁流体动力学）中，这是研究的，尽管并非完全，但是在该项目中要考虑的完全动力学等离子体模型中对此却很少理解。在放松模式之间建立基本联系将变为变为不同，将提高人们对基本等离子体物理学的理解。该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响来审查标准，认为通过评估的评估被认为是宝贵的支持。

项目成果

Turbulent Magnetogenesis in a Collisionless Plasma

无碰撞等离子体中的湍流磁发生

• DOI: 10.3847/2041-8213/ac36cf
• 发表时间: 2021
• 期刊: The Astrophysical journal
• 作者: Pucci, F.;Viviani, M.;Valentini, F.;Lapenta, G.;Matthaeus, W. H.;Servidio, S.
• 通讯作者: Servidio, S.

Pressure–Strain Interaction as the Energy Dissipation Estimate in Collisionless Plasma

• DOI: 10.3847/1538-4357/ac5d3e
• 发表时间: 2022-02
• 期刊: The Astrophysical Journal
• 作者: Y. Yang 杨;W. Matthaeus;Sohom Roy;V. Roytershteyn;T. Parashar;R. Bandyopadhyay;Minping 敏平 Wan 万

Strategies for Determining the Cascade Rate in MHD Turbulence: Isotropy, Anisotropy, and Spacecraft Sampling

• DOI: 10.3847/1538-4357/ac8f90
• 发表时间: 2022-09
• 期刊: The Astrophysical Journal
• 作者: Yanwen Wang;R. Chhiber;S. Adhikari;Yan Yang;R. Bandyopadhyay;M. Shay;S. Oughton;W. Matthaeus;M. Cuesta

Quantifying the Agyrotropy of Proton and Electron Heating in Turbulent Plasmas

• DOI: 10.3847/1538-4357/acb25a
• 发表时间: 2023-02
• 期刊: The Astrophysical Journal
• 作者: Yan Yang;F. Pecora;W. Matthaeus;Sohom Roy;M. Cuesta;A. Chasapis;T. Parashar;R. Bandyopadhyay;D. Gershman;B. Giles;J. Burch

Relativistic Particle Transport and Acceleration in Structured Plasma Turbulence

• DOI: 10.3847/1538-4357/ac5332
• 发表时间: 2021-12
• 期刊: The Astrophysical Journal
• 作者: O. Pezzi;P. Blasi;W. Matthaeus