SHINE: Plasma Heating During Coronal Mass Ejections

该研究小组将确定日冕物质抛射（cme）期间等离子体加热的机制，通过对太阳动力学天文台（SDO）航天器上的大气成像组件（AIA）仪器观测到的日冕物质抛射（cme）进行时间依赖电离分析。在他们的数据分析中，研究小组将定量地限制等离子体加热到低太阳高度，在那里大部分加热发生，应用等离子体密度诊断，然后评估具有不同等离子体加热参数化和速率的广泛模型，以确定需要多少加热来匹配AIA观测。然后，研究小组将测试三种最有希望的候选加热机制理论，即：(1)大规模喷发后电流片加热，(2)通量绳膨胀和松弛期间的小规模磁重联事件，以及(3)高能粒子。提出建议的团队将使用CME的三维模拟来预测电流片加热等离子体的观测特征，这将有助于阐明CME电流片对CME爆发是否具有能量重要性。该团队还将对膨胀的圆柱形磁通绳进行模拟，以确定磁重联和弛豫之间的关系，以及确定等离子体加热的时空依赖性。此外，他们将模拟包含在膨胀通量绳中的高能粒子的真实几何形状，以确定在CME等离子体密度下降之前，非热粒子是否有足够的时间加热CME等离子体。该项目的结果将发表在广泛使用的同行评议期刊上。由于日冕物质抛射是空间天气的重要驱动因素，因此对日冕物质抛射早期演化的研究也可以改善空间天气预报。这个研究小组将应用由实验室等离子体物理社区开发的传统数值代码来解决太阳物理中的一个重要问题。通过这种方式，该团队将加强这两个社区之间的跨学科联系，同时服务于双方的研究兴趣。该项目的组成部分将由本科生暑期实习生执行，他们由美国国家科学基金会通过哈佛-史密森天体物理中心的本科生太阳物理研究经验（REU）计划单独资助。这个本科干部队伍将包括传统上在科学领域代表性不足的群体的成员。

This research team will determine the mechanisms responsible for plasma heating during coronal mass ejections (CMEs), by performing a time-dependent ionization analysis of CMEs observed by the Atmospheric Imaging Assembly (AIA) instrument on the Solar Dynamics Observatory (SDO) spacecraft. In their data analysis, the team will quantitatively constrain plasma heating to low solar altitudes where most of the heating occurs, apply plasma density diagnostics, and then assess a wide range of models with different plasma heating parameterizations and rates, in order to determine how much heating is required to match AIA observations. The research team will then test the three most promising candidate heating mechanism theories, which are (1) heating by the large-scale post-eruption current sheet, (2) small-scale magnetic reconnection events during flux rope expansion and relaxation, and (3) energetic particles. The proposing team will use three-dimensional simulations of CMEs to predict the observational signatures of plasma heating by the current sheet, which will help elucidate whether or not CME current sheets are energetically important to CME eruptions. The team will also perform simulations of an expanding cylindrical flux rope to determine the relationship between magnetic reconnection and relaxation, as well as to determine the spatial and temporal dependence of plasma heating. In addition, they will perform simulations of energetic particles contained within expanding flux ropes in realistic geometries, in order to determine whether there is enough time for non-thermal particles to heat CME plasma before its density drops.Results from this project will be published in widely available peer reviewed journals. Since CMEs are significant drivers of space weather, this research on the early evolution of CMEs can also improve space weather forecasts. This research team will be applying a legacy numerical code developed by the laboratory plasma physics community to an important problem in solar physics. In this way, the team will strengthen interdisciplinary ties between these two communities while serving the research interests of both. Components of this project will be performed by undergraduate summer interns who are separately funded by the NSF through a solar physics Research Experience for Undergraduates (REU) program at the Harvard-Smithsonian Center for Astrophysics. This undergraduate cadre will include members of traditionally underrepresented groups in science.