Collaborative Research: Electron Heat Flux Regulation in the Solar Wind

合作研究：太阳风中的电子热通量调节

• 批准号: 2203319
• 负责人: Chadi Salem
• 金额: $ 28.73万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203319&HistoricalAwards=false
• 关键词: Collaborative; Research; Electron; Heat; Flux

Understanding and characterizing fundamental processes that take place within the heliosphere and throughout the universe is important, and it could be vital for future human explorations of space, as well as for studying the space environmental impact on modern civilization. Solar wind is the medium through which harmful radiation travels. An accurate description of the solar wind is necessary to understand the propagation of these disturbances from the Sun to the Earth. This project studies solar wind physics. The work supports training of a graduate student and post-doctoral researcher.The research aims to address the compelling science question of "what regulates the solar wind heat flux?" The electrons in the solar wind efficiently conduct heat, thus carrying the heat flux along the anti-sunward direction. Among physical processes that regulate the heat flux, whistler heat-flux instabilities are suggested as being important in the collisionless heat flux regime, while in the collisional regime, the binary collisions are the classical regulation mechanism. Both processes compete against the radial expansion effects. The relative importance of these competing processes, that is, instabilities, collisions, and expansion, remains an outstanding and thus, together they constitute a compelling research topic. The project will use the self-consistent quasilinear theory and kinetic theory of collisions in magnetized plasma to model the evolution of the waves and electron heat flux in the radially-varying solar wind. The theory will be driven by inputs from, and tested against, the well-calibrated measurements of the solar wind electron distribution function from various spacecraft between 0.3 and 1 AU, as well as proton parameters, magnetic field and plasma wave data. Such an integrated and collaborative research on the nature of solar wind electrons and the heat flux they carry will greatly contribute toward improving our understanding of the fundamental processes that take place within the heliosphere.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.

了解和描述日光层内和整个宇宙中发生的基本过程非常重要，这对于人类今后的空间探索以及研究空间环境对现代文明的影响都是至关重要的。太阳风是有害辐射传播的媒介。对太阳风的准确描述对于理解这些扰动从太阳到地球的传播是必要的。这个项目研究太阳风物理。这项工作支持对研究生和博士后研究人员的培训。这项研究旨在解决一个引人注目的科学问题：“是什么调节了太阳风的热通量？”太阳风中的电子有效地传导热量，从而沿着反太阳方向携带热流。在调节热流的物理过程中，哨声热流不稳定性在无碰撞热流区起重要作用，而在碰撞区，双碰撞是经典的调节机制。这两个过程都与径向膨胀效应相竞争。这些相互竞争的过程的相对重要性，即不稳定性、碰撞和扩张，仍然是一个突出的问题，因此，它们共同构成了一个引人注目的研究课题。该项目将使用磁化等离子体中碰撞的自洽准线性理论和动力学理论来模拟径向变化的太阳风中波和电子热流的演变。该理论将由各种航天器在0.3到1AU之间对太阳风电子分布函数的精确测量以及质子参数、磁场和等离子体波数据的输入驱动并进行测试。这种对太阳风电子的性质及其携带的热通量的综合和协作研究将极大地有助于提高我们对日球层内发生的基本过程的理解。这一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智力优势和更广泛的影响审查标准进行评估，被认为值得支持。