Multi-ion Dynamics of the Slow Solar Wind in Coronal Streamers

日冕流中缓慢太阳风的多离子动力学

• 批准号: 1059838
• 负责人: Leon Ofman
• 金额: $ 32.1万
• 依托单位: Catholic University of America
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-15 至 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1059838&HistoricalAwards=false
• 关键词: Multi; ion; Dynamics; Slow; Solar

The Principal Investigator (PI) will perform a computational study of the formation and acceleration of the multi-ion solar wind in coronal streamers. He is motivated by the fact that previous MHD studies that have attempted to describe the solar wind plasma as a single fluid did not reproduce the observed properties of solar wind ions. In this effort, the PI will investigate the solar wind's multi-ion dynamics and compositional variations by developing comprehensive multidimensional and multi-fluid models of coronal streamers that incorporate heavy ions along with protons and electrons as separate but coupled fluids. He will study the effects of preferential heavy-ion heating and ion temperature anisotropies by including empirical heating terms, as well as wave heating and acceleration terms, in his new models. The PI will perform detailed comparisons between his models and available spectroscopic observations by calculating the ultraviolet (UV) emissivity expected from his multi-fluid model output. The computation of coronal emission based on the PI's models will allow him to estimate the expected intensity of UV spectral lines that will be detected using future coronagraphic instruments. This research will lead to a better understanding of the slow solar wind's composition and structure, as well as of the acceleration and heating processes that affect its plasma components. This project will promote research and education by involving a graduate student who belongs to an underrepresented minority group, as well as by training a postdoctoral scholar. The numerical codes developed in this project will strengthen the nation's computational infrastructure by providing massively parallel multi-fluid models for use by other researchers. The PI's multidimensional, multi-fluid numerical modeling codes will be made available to the broader scientific community for ongoing solar wind research, as well as for other applications where multi-ion plasmas are present, such as in laboratory and astrophysical plasmas.

首席研究员（PI）将对日冕流光中多离子太阳风的形成和加速进行计算研究。他的动机是，之前的MHD研究试图将太阳风等离子体描述为一种单一的流体，但并没有重现观测到的太阳风离子的特性。在这项工作中，PI将研究太阳风的多离子动力学和成分变化，通过开发日冕流的综合多维和多流体模型，将重离子、质子和电子作为分离但耦合的流体结合起来。他将研究重离子优先加热和离子温度各向异性的影响，在他的新模型中包括经验加热项，以及波加热和加速项。PI将通过计算他的多流体模型输出的预期紫外线（UV）发射率，对他的模型和现有的光谱观测进行详细的比较。基于PI模型的日冕辐射计算将使他能够估计未来日冕仪器检测到的紫外线光谱线的预期强度。这项研究将有助于更好地了解慢速太阳风的组成和结构，以及影响其等离子体成分的加速和加热过程。该项目将促进研究和教育，涉及一名属于代表性不足的少数群体的研究生，以及培养一名博士后学者。在这个项目中开发的数字代码将通过为其他研究人员提供大规模并行多流体模型来加强国家的计算基础设施。PI的多维、多流体数值模拟代码将提供给更广泛的科学界，用于正在进行的太阳风研究，以及存在多离子等离子体的其他应用，如实验室和天体物理等离子体。