Estimation of the westward auroral electrojet current using sparse magnetometer chain data
We investigate 1-D models of the westward substorm electrojet using magnetic field observations along a meridian chain of stations. We review two respective linear models from Kotikov et al. (1987) and Popov et al. (2001) with a large number of elementary currents at fixed positions. These models ca...
| Published in: | Annales Geophysicae |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Publications
2020
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/angeo-38-109-2020 https://noa.gwlb.de/receive/cop_mods_00050399 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00050010/angeo-38-109-2020.pdf https://angeo.copernicus.org/articles/38/109/2020/angeo-38-109-2020.pdf |
| Summary: | We investigate 1-D models of the westward substorm electrojet using magnetic field observations along a meridian chain of stations. We review two respective linear models from Kotikov et al. (1987) and Popov et al. (2001) with a large number of elementary currents at fixed positions. These models can be applied to a magnetometer chain with many magnetic stations. A new nonlinear method with one current element is designed for cases with a small number of stations. We illustrate the performance of these methods using data from the IMAGE (International Monitor for Auroral Geomagnetic Effects) and Yamal Peninsula stations. Several corrective measures are proposed to account for unphysical solutions or local extrema from the optimized functions. We also advertise a generic maximum likelihood approach to a problem that is feasible for any empiric model. |
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