SHINE: Driving Global Heliospheric Magnetohydrodynamics (MHD) Models with Tomographically-Determined Lower Boundary Conditions

这一提议的目的是利用层析技术确定的太阳下部边界的电子密度(Ne)和温度(T)值来驱动现有的日光层磁流体动力学三维(3D)模型。这些新的日球层模型将被用来研究准稳态太阳风、日冕物质抛射(CME)传播、日冕物质抛射驱动的冲击以及相关的高能粒子事件。层析测定的数据来源将包括莫纳罗亚太阳天文台的Mark IV白光日冕仪、STEREO(日地关系天文台)上的COR1(白光日冕内冕仪)、Yohkoh(日地关系观测台)的SXT(软X射线望远镜)、STEREO(太阳和日球层观测台)的EUVI(极端紫外线成像仪)、SOHO(太阳/日球层观测台)的EIT(极端紫外线成像望远镜)、Solar-B(太阳动力学观测站)的XRT(X射线望远镜)以及AIA(大气层成像组件)。在这个为期三年的合作项目中，伊利诺伊大学将生成3D层析模型，并使用它们来指定密歇根大学基于BATS-R-US MHD代码的3D日球层模型的下边界条件。当前一代的3D日球层模型使用天气磁图来确定下边界的磁场。确定Ne和T的下界限值要困难得多，研究人员被迫使用简单化的假设(例如密度可以通过标度因数与磁场大小相关)。层析成像提供了一个很好的机会来确定日冕中Ne和T的真实边界值。根据这项研究拨款开发的层析成像模型将有许多应用，包括确定对日冕加热功能的限制，并提供3D背景以帮助解释高分辨率紫外线(UV)光谱。该项目将支持伊利诺伊大学电气和计算机工程系与密歇根大学海洋、大气和空间科学系之间的跨学科合作，并将直接支持本科生和研究生教育。

The aim of this proposal is to drive existing three-dimensional (3D) heliospheric magnetohydrodynamics (MHD) models with tomographically determined values of electron density (Ne) and temperature (T) at the lower solar boundary. These new heliospheric models then will be used to study the quasi-steady solar wind, coronal mass ejection (CME) propagation, CME-driven shocks, and the associated energetic particle events. The sources of data for the tomographic determinations will be the Mark IV white-light coronagraph at Mauna Loa Solar Observatory, the COR1 (white-light coronagraph for inner corona) coronagraph on STEREO (solar terrestrial relations observatory), SXT (soft X-ray telescope) on Yohkoh, EUVI (extreme ultraviolet imager) on STEREO, EIT (extreme ultraviolet imaging telescope) on SOHO (solar and heliospheric observatory), XRT (X-ray telescope) on Solar-B, and AIA (atmospheric imaging assembly) on the Solar Dynamics Observer spacecraft. In this three-year collaborative project, the University of Illinois will generate the 3D tomographic models and use them to specify lower boundary conditions for the University of Michigan 3D heliosphere model based on the BATS-R-US MHD code. The current generation of 3D heliospheric models uses synoptic magnetograms to establish the magnetic field at the lower boundary. Determination of the lower boundary values of Ne and T is far more problematic, and researchers are compelled to use simplistic assumptions (such as that the density can be related to the magnetic field magnitude by a scale factor). Tomography offers an excellent opportunity to determine realistic boundary values of Ne and T in the corona. The tomographic models developed under this research grant will have numerous applications, including determining the constraints on coronal heating functions and providing a 3D context to help interpret high-resolution ultra-violet (UV) spectra. This project will support an interdisciplinary collaboration between the Department of Electrical and Computer Engineering at the University of Illinois and Department of Ocean, Atmospheric and Space Science at the University of Michigan, and will directly support undergraduate and graduate education.