Magnetopause Standoff Position Changes and Geosynchronous Orbit Crossings: Models and Observations

• Published in: Space Weather 2023-06, Vol.21 (6), p.n/a
• Main Authors: Collado‐Vega, Y. M., Dredger, P., Lopez, R. E., Khurana, S., Rastaetter, L., Sibeck, D., Anastopulos, M.
• Format: Article
• Language: English
• Subjects: Contingency; Contingency tables; Coronal mass ejection; crossings; Dynamic pressure; Earth; Earth magnetosphere; Environment models; Geosynchronous orbits; GOES satellites; Interplanetary magnetic field; Magnetic fields; Magnetohydrodynamics; Magnetopause; Magnetospheric-solar wind relationships; model observations; Modelling; Satellite observation; Satellites; Solar magnetic field; Solar wind; Solar wind parameters; Solar wind speed; Step functions; validation; Wind speed
• ISSN: 1542-7390; 1539-4964; 1542-7390
• DOI: 10.1029/2022SW003212

This research examines the ability of current physics‐based models to predict the magnetopause location. We use the Run‐On‐Request capabilities at the Community Coordinated Modeling Center at NASA GSFC with 4 magnetohydrodynamic (MHD) models. The magnetopause position prediction and response time to the solar wind changes is then compared to extreme solar wind conditions where magnetopause crossing of geosynchronous orbit have been observed by the Geostationary Operational Environmental Satellite (GOES) satellites. Rigorous analysis/comparison of observations and models is critical in determining magnetosphere dynamics for model validation. This paper is a preliminary effort defining the metrics necessary to understand the current magnetosphere model capabilities and challenges. Results show that there are discrepancies between the MHD models' standoff positions of the dayside magnetopause for the same solar wind conditions on events that included (a) an increase in solar wind dynamic pressure and a step function in the Interplanetary Magnetic Field Bz component; (b) nominal solar wind conditions (values of approximated 400 km/s for solar wind speed and 5 nT for the magnetic field magnitude) with a northward IMF; and (c) compression caused by several coronal mass ejections impacting the near Earth environment. Overall, the models predicted different magnetopause subsolar locations sometimes in the order of 3 RE. Contingency tables were calculated to show model performance in comparison with the data observed with the GOES 13/15 geosynchronous orbit for extreme events and skill scores were calculated. Plain Language Summary Earth's magnetopause is the boundary that separates the solar wind from Earth's magnetosphere. Its location and dependence on solar wind parameters has been studied via simulations and observations. In this study, we analyzed events where the solar wind conditions were very dynamic, including extreme conditions during which geosynchronous orbit crossings were detected by the Geostationary Operational Environmental Satellite 13 and 15 satellites. Our results show that the models give very different magnetopause positions sometimes showing geosynchronous orbit crossings where they were not observed. Contingency tables and skill scores were calculated to analyze the discrepancies between the models for the extreme events. Key Points A preliminary effort into defining metrics necessary to understand the current magnetosphere models' capabili