Validation of the AWSoM Solar Wind Magnetic Field Model with Upstream Mercury Solar Wind Conditions from MESSENGER Observations

Previous studies from MESSENGER have shown that plasma dynamical processes within Mercury’s magnetosphere are strongly driven by its solar wind conditions. However, the upstream region of Mercury’s magnetosphere has no constant solar wind monitor to provide information about them when the spacecraft is inside the planet’s plasma environment, which emphasizes the importance of a solar wind model to accurately predict their conditions. This project aims to validate and assess the capability of the Alfvén Wave Solar Atmosphere Model (AWSoM) developed at the University of Michigan in predicting solar wind Interplanetary Magnetic Field (IMF) conditions (polarity and magnitude) by comparing its simulated outputs with solar wind data from MESSENGER. We have identified solar wind intervals in the MESSENGER’s magnetic field measurements from three Carrington Rotations (i.e. CR 2132, 2138, and 2139) to be compared with AWSoM’s simulation results using ADAPT-GONG magnetograms as the input. Each of the 12 ADAPT realizations for each Carrington rotation period was compared with the solar wind data IMF measurements, and assessed on how well they agree with MESSENGER’s observations. The comparative analysis technique Dynamic Time Warping (DTW) is used to make this assessment in this study, due to the time-shifted alignment typically observed between the observed and simulated solar wind data. The technique is implemented on all 12 realizations of each simulation run to determine the “best-fit” comparison, accounting for the time shift, using the DTW “cost” or “score” parameter. The data-model comparison methods and results presented in this study will contribute to future studies related to solar activity and solar wind IMF, and applied towards other planetary environments (e.g. MAVEN for Mars) and future spacecraft missions to Mercury (e.g. Bepi-Colombo).