Picturing the global magnetosphere during storms and substorms by data-mining decades of spacecraft magnetometer observations
| Autor: | Stephens, G., Sitnov, M., Weigel, R., Turner, D., Tsyganenko, N., Rogers, A., Genestreti, K., Slavin, J., Arnold, H. |
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| Jazyk: | angličtina |
| Rok vydání: | 2023 |
| Zdroj: | XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
| DOI: | 10.57757/iugg23-3583 |
| Popis: | The magnetosphere undergoes global dynamical reconfigurations termed storms and substorms in response to solar wind driving. Understanding how the 3D magnetic field and associated current systems evolve in time during these events is critical to characterizing the magnetosphere system. However, modeling storms and substorms using first-principles approaches is complicated because non-ideal magnetohydrodynamical processes, such as the formation of the storm-time ring current, thin current sheets, and magnetic reconnection, are key to their description. As such, several unanswered questions persist regarding the global morphology of these events and on their driving mechanisms. Here, we address these questions by empirically reconstructing the global 3D magnetic field and electric currents from decades of spacecraft magnetometer observations. For a given time of interest, the archive of observations is mined to form a subset of data from other times when the magnetosphere was in a similar storm and/or substorm state. This subset of data is used to fit an empirical model of the magnetic field that analytically describes the key magnetospheric current systems. This process is then repeated for each snapshot during an event, allowing for a quantitative dynamical picture to be reconstructed from the magnetometer data. We demonstrate that this data-mining based empirical approach reconstructs the primary features of substorms, including the thinning and stretching of the magnetotail followed by its rapid dipolarization, as well as the build-up of the storm-time ring current and pressure. This approach also locates the site of magnetotail reconnection during these events as confirmed by comparison with in-situ observations. The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) |
| Databáze: | OpenAIRE |
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