Collaborative Research: Plasma Heating and Energy Partition in Flares and Coronal Mass Ejections (CMEs)

太阳爆发，以耀斑和日冕物质抛射（CME）的形式出现，是太阳大气层中的剧烈爆炸，将数百万吨的热等离子体推进行星际空间。 它们是太阳系中最大的能量释放事件，也是地球空间天气扰动的主要驱动力。 当它们指向地球时，它们会对人类的努力产生不利影响，如空中交通通信，电网和卫星，并对太空旅行的宇航员造成危险。 因此，了解这些强大事件背后的物理学非常重要。 人们普遍认为，磁场的突然和剧烈的重新配置是太阳爆发中能量释放的主要过程。 然而，磁能转化为加热和等离子体运动的细节还没有得到很好的理解。 在这个为期三年的项目中，将采用最先进的计算机模拟和卫星观测，通过建模和系统地研究耀斑和日冕物质抛射中的能量转移和等离子体加热，在这一重要问题上取得进展。 该项目将支持一名博士生的论文研究，从而促进NSF的教育目标。这个为期三年的项目将采用先进的磁流体动力学（MHD）数值模拟来模拟太阳喷发（理想化和观察到的情况下）。 模拟结果将用于确定负责喷发期间能量转换和等离子体加热的物理机制，并量化其各自的贡献。 这些数值研究将辅之以对现有航天器的高节奏和高分辨率观测的详细分析，使用成熟的分析工具从观测数据中获取热信息。 该项目旨在回答有关太阳爆发的几个公开问题。 首先，它将研究在太阳耀斑的脉冲阶段加热等离子体的物理机制，并量化在这一阶段的能量分配。 第二，它将探索在太阳耀斑后期加热电流片区域等离子体的物理机制。 第三，它将调查最近发现的“热等离子体通道”是如何形成的，并在喷发的早期阶段加热到超过1000万开氏度的温度。 最后，它将研究如何喷发等离子体被加热，并在其传播过程中的CME演变。 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。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。

Solar eruptions, in the form of flares and coronal mass ejections (CMEs), are violent explosions in the Sun's atmosphere that propel millions of tons of hot plasma into interplanetary space. They are the largest energy-release events in the solar system and the main driver of space weather disturbances at Earth. When directed towards the Earth, they can adversely affect human endeavors such as air traffic communications, power grids, and satellites, and be hazardous to astronauts traveling in space. It is therefore important to understand the physics behind these powerful events. It is widely accepted that the sudden and violent reconfiguration of magnetic fields is the main process that enables the release of energy in solar eruptions. However, the details of the conversion of magnetic energy into heating and plasma motion are not well understood. In this three-year project, state-of-the-art computer simulations together with satellite observations will be employed to make progress on this important problem, by modeling and systematically investigating energy transfer and plasma heating in flares and CMEs. The project will support the dissertation research of a PhD student and thus foster the educational goals of the NSF.This three-year project will employ sophisticated magnetohydrodynamic (MHD) numerical simulations to model solar eruptions (for both idealized and observed cases). The simulation results will be used to identify the physical mechanisms responsible for energy conversion and plasma heating during eruptions and to quantify their respective contributions. These numerical investigations will be complemented with detailed analysis of high-cadence and high-resolution observations from current spacecraft, using well-developed analysis tools for deriving thermal information from observational data. This project aims to answer several open questions about solar eruptions. First of all, it will examine the physical mechanisms that heat plasma during the impulsive phase of solar flares and quantify the energy partition in this phase. Secondly, it will explore the physical mechanisms responsible for heating plasma in the region of the current sheet in the late phase of solar flares. Thirdly, it will investigate how the recently discovered "hot plasma channels" are formed and heated to temperatures of more than 10 million degrees Kelvin in the early stages of an eruption. Finally, it will examine how erupting plasma is heated and evolves during its propagation within a CME. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.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.