Collaborative Research: Heating the Solar Chromosphere Through Plasma Turbulence

该项目的目标是对太阳大气加热的起源提供详细的可验证的解释。 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。然而，太阳大气层的区域，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，一种以超过400公里/秒的速度通过地球的带电粒子流。快速变化的辐射和太阳风都对航天器和宇航员造成了危险，并对地球产生了一些重要的影响。一个长期存在的谜团阻碍了科学家们对色球层和日冕的理解和准确建模。在离太阳“表面”不远的地方，太阳大气层的温度上升了两到三倍。这个项目的目标是提供一个解释这种加热的起源。 该项目还将提供机会，招募和培训波士顿大学等离子体和太阳物理学、模拟和建模方面的学生研究人员。 波士顿大学PI的许多本科研究生，其中约一半是女性，继续研究生院。这项研究将检查从光球层出现的太阳等离子体流是否可以将足够的能量转移到太阳大气的湍流等离子体中，这反过来又会充分加热色球层，以解释所观察到的紫外光谱是否起源于那里。它还将评价这一机制是否能够解释色球光谱观测。这需要四个相互关联的研究任务：（1）求解中性对流气体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;以及（4）将所产生的电子加热并入辐射输运代码中以评估其对色球辐射的影响。这项研究结合了NSF/DOE基础科学和工程合作伙伴关系所涵盖的几个研究领域。

The goal of this project is to provide a detailed verifiable explanation of the origin of the heating of the solar atmosphere. Most of the light reaching Earth originates at the 'surface' of the sun, a region called the photosphere. However, the regions of the solar atmosphere 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 that pass the Earth at speeds in excess of 400km/s. Both the rapidly changing radiation and the solar wind create hazards for spacecraft, astronauts, and have a number of important terrestrial impacts. A long-standing mystery has prevented scientists from understanding and accurately modeling the chromosphere and corona. A short distance above the 'surface' of the sun, the solar atmosphere's temperature jumps up by a factor of two to three. The goal of this project is to provide an explanation of the origin of this heating. The project will also provide opportunities to recruit and train student researchers in plasma and solar physics, simulations, and modeling at the Boston University. Many of the Boston University PI's undergraduate research advisees, about half of whom are women, have continued on to graduate school. This research will examine whether solar plasma flows emerging from the photosphere can transfer sufficient energy into turbulent plasma of the solar atmosphere, which, in turn, will heat the chromosphere sufficiently to explain whether the observed UV spectra originate there. It will also evaluate whether this mechanism can account for chromospheric spectral observations. This requires four 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; and (4) incorporating the resulting electron heating into a radiative transport code in order to evaluate its impact on chromospheric radiance. This research combines several research areas encompassed by the NSF/DOE Partnership in Basic Science and Engineering.