SHINE: Connecting Electron Thermodynamics and Microphysical Processes: A Puzzle for the Evolution of the Solar Wind

SHINE：连接电子热力学和微物理过程：太阳风演化之谜

• 批准号: 1622498
• 负责人: Chadi Salem
• 金额: $ 36万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1622498&HistoricalAwards=false
• 关键词: SHINE; Connecting; Electron; Thermodynamics; Microphysical

For a long time, it has been unclear and a matter of debate to what degree electron-kinetic effects play a role for the acceleration and the evolution of the solar wind compared to other processes, such as the dissipation of turbulent fluctuations. For the first time, our observational capabilities, with the unprecedented quality of the solar cycle worth of Wind electron data that we are producing, combined with a theoretical analysis will allow us to quantitatively connect electron thermodynamics in the solar wind and microphysical processes and better determine the role of electrons for the evolution of the solar wind. This 3-year SHINE project is expected to improve present understanding of the physical processes that are relevant for the generation and evolution of the solar wind from a very fundamental plasma-physical perspective based on first principles. It will also provide much needed input for the development of predictive physics-based solar-wind models. Including more accurate description of electron physics in such models will lead to major improvements of our understanding of space-weather processes, the propagation of energetic-particle events, as well as the propagation of cosmic rays throughout the heliosphere.This 3-year SHINE project describes an integrated research program to study the microphysical processes that regulate the kinetic and non-thermal features of solar wind electrons, like the electron core and halo drifts, and the electron strahl structure. It will investigate the micro-instabilities generated by drifts, heat flux and temperature anisotropy, as well as their contributions to solar wind turbulence. The research will be based on in-situ observations of solar wind electron distribution functions, proton measurements, as well as magnetic field and plasma wave data from the Wind spacecraft. A hot plasma dispersion solver will be used to determine the theoretical thresholds and growth rates of electron-driven micro-instabilities.The electron microphysical processes addressed in this proposal have a broader application than the interplanetary medium, as they occur in the solar corona, the coronae of other stars and compact astrophysical objects, and in other more exotic environments in the universe such as jets and supernova blast waves. Furthermore, the topic of electron microphysics in the solar wind and in space plasma is one of the primary science focus topics by the heliophysics community in the USA, in particular SHINE. In the past, the project team has convened dedicated sessions at the NSF-funded SHINE Workshops in 2014 and 2015, which have received very positive feedback from the heliophysics community. The investigators plan to continue to lead the focus group and the science discussions to foster more, multi-disciplinary, collaborations within the space physics community, involving theory, numerical simulations, observations and data analysis. As part of this project, they propose a follow-up session at the 2016 SHINE Workshop. This science topic is also of great importance in the preparation of the upcoming NASA mission Solar Probe Plus and ESA mission Solar Orbiter, one of their key science goals being to explore in-situ the fundamental microphysical plasma processes at the origin of the heating of the solar corona, acceleration of the solar wind and the evolution of the heliosphere including CMEs and transients. This research project will foster a close work collaboration between the UC Berkeley and the UNH. It will support two young researchers in early phases of their scientific careers and a graduate student at UC Berkeley. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.

长期以来，人们一直不清楚电子动力学效应与其他过程（如湍流波动的消散）相比，在多大程度上对太阳风的加速和演变起作用，这是一个有争议的问题。 这是第一次，我们的观测能力，与我们正在生产的前所未有的太阳周期风电子数据的质量相结合，理论分析将使我们能够定量地连接太阳风和微物理过程中的电子热力学，并更好地确定电子的作用。 这个为期3年的SHINE项目预计将从基于第一原理的非常基本的等离子体物理角度提高目前对太阳风产生和演变相关物理过程的理解。 它还将为开发基于预测物理学的太阳风模型提供急需的投入。 在这种模式中包括更精确的电子物理描述将导致我们对空间天气过程，能量粒子事件的传播以及宇宙射线在整个日光层中的传播的理解的重大改进。这个为期3年的SHINE项目描述了一个综合研究计划，以研究调节太阳风电子的动力学和非热特征的微物理过程，如电子核和晕漂移，以及电子strahl结构。 它将研究漂移、热通量和温度各向异性产生的微观不稳定性，以及它们对太阳风湍流的贡献。 这项研究将基于对太阳风电子分布函数的现场观测、质子测量以及来自Wind航天器的磁场和等离子体波数据。 热等离子体色散解算器将用于确定电子驱动的微不稳定性的理论阈值和增长率，本提案中涉及的电子微物理过程比行星际介质具有更广泛的应用，因为它们发生在太阳日冕、其他恒星和致密天体的日冕中，以及宇宙中其他更奇特的环境中，如喷流和超新星爆炸波。 此外，太阳风和空间等离子体中的电子微观物理学专题是美国太阳物理学界，特别是“阳光”项目的主要科学重点专题之一。 在过去，项目团队在2014年和2015年在NSF资助的SHINE研讨会上召开了专门会议，这些研讨会收到了来自太阳物理界的非常积极的反馈。 研究人员计划继续领导焦点小组和科学讨论，以促进空间物理学界更多的多学科合作，涉及理论、数值模拟、观测和数据分析。 作为该项目的一部分，他们建议在2016年SHINE研讨会上举行后续会议。 这一科学专题对于准备即将进行的美国航天局使命太阳探测器增强型飞行任务和欧空局使命太阳轨道飞行器飞行任务也非常重要，它们的主要科学目标之一是在太阳日冕加热、太阳风加速和包括日冕物质抛射和瞬变在内的日光层演变的起源处就地探索基本微物理等离子体过程。 这个研究项目将促进加州大学伯克利分校和UNH之间的密切合作。 它将支持两名年轻的研究人员在他们的科学生涯的早期阶段和一名研究生在加州大学伯克利分校。 该项目的研究和EPO议程支持AGS部门在发现，学习，多样性和跨学科研究方面的战略目标。