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

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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.