SHINE: Multi-Spacecraft Observational Study and Magnetohydrodynamic (MHD) Modeling of Interplanetary Coronal Mass Ejections (ICMEs) Observed in Conjunction

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Coronal Mass Ejections (CMEs) are a complex and fundamental component of space weather. They have the potential to do significant damage to satellites, power grids, and humans in space. CMEs change in significant ways as they propagate through the interplanetary medium. There are only a few locations between the Sun and the Earth where measurements of the ICMEs (Interplanetary Coronal Mass Ejections) have been made. As such, this 3-year SHINE project is potentially transformative as it plans to use data and models to examine ICMEs that hit Mercury and Earth. The goals are to determine how their properties evolve, how solar wind interactions change them, and what critical factors affect the direction of the magnetic field in them. This last point is particularly important as the direction of the field when it hits Earth plays a very large role in the effect that the CME has on electric and telecommunications systems. The outcomes of this study have the potential to vastly improve the science behind prediction models used in space hazard early warning systems. The main goal of this SHINE project is to develop the physical understanding of interplanetary coronal mass ejection (ICME) propagation and evolution in the inner heliosphere inside 1 AU. To accomplish this goal, the project will use multi-spacecraft observations of the same ICME events at Mercury (MESSENGER) and at 1 AU (ACE, WIND, STEREO), in conjunction with magnetohydrodynamic (MHD) models of these events to focus on ICME magnetic field (strength and direction), speed, and shock structure evolution from 0.3 AU to 1 AU. The main efforts of the analyses include force-free field fitting of the magnetic ejecta to determine the flux rope orientation and axial magnetic field strength at Mercury and at 1 AU, ICME shock shape determination at both distances, solar wind velocity estimation at Mercury (from proxies as well as models), and MHD simulations of real ICME events in order to discern global structure and changes during propagation. MESSENGER has now amassed a large dataset of ICMEs from years of observations at Mercury's heliocentric distances, and so this project is very timely and will lay the groundwork in mapping ICME evolution in preparation for the upcoming Solar Orbiter and Solar Probe Plus missions. The three key scientific questions addressed in this project are: (1) how do ICME properties (e.g., magnetic field, speed, shock structure) evolve from Mercury to 1 AU; (2) does the global magnetic field structure inside ejecta change significantly on average from Mercury to 1 AU; and, (3) what are the critical factors that affect change in flux rope orientation during propagation?The project is highly relevant to the NSF's SHINE program, and it will have a strong impact on the SHINE community. SHINE and the broader scientific community will be served through the following avenues. First, databases and results from the project will be made freely available to the scientific community. Second, the project team will engage the SHINE community through the SHINE workshop to take part in a challenge to use the observed ICME events as campaign events to test models. Third, the project will support an early career, female scientist, thereby contributing towards retaining highly qualified young scientists in academic research and promoting the advancement of women in science. Fourth, the Co-Is will teach undergraduate and graduate classes related to space science, and the research results will be incorporated, when possible, into advanced undergraduate and graduate classes. The project team will utilize the scientific outcome of this project to motivate and educate students, teachers, and the public with an appreciation of the importance of solar physics and STEM fields in general by leveraging the special initiatives of the Institute for the Study of Earth, Oceans, and Space (EOS) at UNH. Therefore, the research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.