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

太阳喷发，以耀斑和日冕物质抛射(CME)的形式，是太阳大气中的猛烈爆炸，将数百万吨热等离子体推向星际空间。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，可能会对空中交通通信、电网和卫星等人类活动产生不利影响，并对在太空旅行的宇航员构成危险。因此，理解这些强大事件背后的物理原理是很重要的。人们普遍认为，磁场的突然和猛烈的重新配置是太阳喷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被很好地理解。在这个为期三年的项目中，将利用最先进的计算机模拟和卫星观测，通过对耀斑和日冕物质抛射中的能量转移和等离子体加热进行建模和系统研究，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，从而促进国家自然科学基金会的教育目标。这个为期三年的项目将使用复杂的磁流体(MHD)数值模拟来模拟太阳喷发(无论是理想情况还是观测到的情况)。模拟结果将用于确定喷发期间能量转换和等离子体加热的物理机制，并量化它们各自的贡献。这些数字调查将辅之以对当前航天器的高频率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得出热信息。这个项目旨在回答几个关于太阳喷发的公开问题。首先，它将研究太阳耀斑脉冲阶段加热等离子体的物理机制，并量化这一阶段的能量分配。其次，它将探索负责加热太阳耀斑后期电流片区域等离子体的物理机制。第三，它将研究最近发现的“热等离子体通道”是如何形成的，并在喷发的早期阶段被加热到超过1000万开尔文的温度。最后，它将研究喷发的等离子体在CME内传播过程中如何被加热和演化。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。

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.