Solar Chromospheric Plasma Turbulence and Heating Driven by Neutral-Plasma Coupling

中性等离子体耦合驱动的太阳色层等离子体湍流和加热

• 批准号: 1903416
• 负责人: Meers Oppenheim
• 金额: $ 40.45万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1903416&HistoricalAwards=false
• 关键词: Solar; Chromospheric; Plasma; Turbulence; Heating

Most of the light reaching Earth originates at the "surface" of the sun, a region called the photosphere. The regions immediately above this surface, the solar chromosphere and corona, create most of the dangerous Ultraviolet (UV) and X-ray radiation. These regions also generate the solar wind, a stream of charged particles, a plasma, that reach the Earth at speeds in excess of 400km/s. Both the rapidly changing radiation and the solar wind create space weather that results in hazards for spacecraft, astronauts, and also have a number of important impacts on Earth by inducing current surges and disrupting communication. A long-standing mystery has prevented scientists from understanding and accurately modeling the solar atmosphere: a short distance above the photosphere, the chromosphere's temperature jumps up by almost a factor of two, providing some of the energy that creates the even hotter corona and solar wind. This project will investigate previously unexplored physical processes in the solar chromosphere and develop a more complete physics-based explanation of the origin of the heating. This project will examine whether neutral solar fluid flows, emerging from the photosphere, can transfer sufficient energy into plasma turbulence to heat the chromosphere in order to account for the observed UV spectra. This requires five linked research tasks: (1) solving for plasma drifts and fields when a convecting neutral gas pushes it across magnetic field lines; (2) analyzing the theory of streaming instabilities applicable to the collisional plasma found there; (3) performing a series of kinetic simulations to explore the nonlinear and thermal properties of the resulting turbulence; (4) incorporating the resulting electron heating into a radiative transport code in order to evaluate its impact on chromospheric radiance; and (5) comparing the resulting predictions with observations. This grant will provide opportunities to recruit and train student researchers in plasma and solar physics, simulations, and modeling. This research, the sophisticated simulators, and these students will have an impact far beyond the duration of this grant.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.

大部分到达地球的光都来自太阳的“表面”，一个被称为光球层的区域。 太阳表面上方的区域，即太阳色球层和日冕，产生了大部分危险的紫外线（UV）和X射线辐射。 这些区域还产生太阳风，一种带电粒子流，一种等离子体，以超过400公里/秒的速度到达地球。 快速变化的辐射和太阳风都会产生太空天气，给航天器和宇航员带来危险，并通过诱发电流激增和干扰通信对地球产生许多重要影响。 一个长期存在的谜团阻碍了科学家们理解太阳大气层并对其进行准确建模：在光球上方的一小段距离处，色球层的温度几乎跃升了两倍，提供了一些能量，从而产生了更热的日冕和太阳风。 该项目将调查太阳色球层中以前未探索过的物理过程，并对加热的起源提出更完整的基于物理学的解释。该项目将研究从光球层出现的中性太阳流体流是否能够将足够的能量转移到等离子体湍流中，以加热色球层，从而解释观测到的紫外光谱。 这需要五个相互关联的研究任务：（1）求解中性对流气体推动其穿过磁力线时的等离子体漂移和场;（2）分析适用于碰撞等离子体的流动不稳定性理论;（3）进行一系列动力学模拟以探索由此产生的湍流的非线性和热特性;（4）将由此产生的电子加热纳入辐射传输代码，以评估其对色球辐射的影响;（5）将由此产生的预测与观测结果进行比较。该补助金将提供机会招募和培训等离子体和太阳物理学、模拟和建模领域的学生研究人员。这项研究、复杂的模拟器和这些学生的影响将远远超出该资助的期限。该奖项反映了NSF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。

项目成果

Newly Discovered Source of Turbulence and Heating in the Solar Chromosphere

• DOI: 10.3847/2041-8213/ab75bc
• 发表时间: 2020-02
• 期刊: The Astrophysical Journal Letters
• 作者: M. Oppenheim;Y. Dimant;W. Longley;A. Fletcher

Multifluid Simulation of Solar Chromospheric Turbulence and Heating Due to Thermal Farley–Buneman Instability

法利-布内曼热不稳定性引起的太阳色球层湍流和加热的多流体模拟

• DOI: 10.3847/1538-4357/acc5e5
• 发表时间: 2023
• 期刊: The Astrophysical Journal
• 作者: Evans, Samuel;Oppenheim, Meers;Martínez-Sykora, Juan;Dimant, Yakov;Xiao, Richard
• 通讯作者: Xiao, Richard