Carter, JA;
Samsonov, AA;
Milan, SE;
Branduardi‐Raymont, G;
Ridley, AJ;
Paxton, LJ;
Anderson, BJ;
... Edwards, T; + view all
(2021)
Field-Aligned Current During an Interval of BY-Dominated Interplanetary-Field; Modeled-to-Observed Comparisons.
Journal of Geophysical Research: Space Physics
, 126
(12)
, Article e2021JA029722. 10.1029/2021ja029722.
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Abstract
We model an interval of remarkable interplanetary magnetic field (IMF), for which we have a comprehensive set of observational data. This interval is associated with the arrival of an interplanetary coronal mass ejection. The solar wind densities at the time are particularly high and the IMF is primarily northward over many hours. This results in strong auroral emissions within the polar cap in a cusp spot, which we associate with lobe reconnection at the high-latitude magnetopause. We also observe areas of upwards field-aligned current (FAC) within the summer Northern Hemisphere polar cap that exhibit large current magnitudes. The model can reproduce the spatial distribution of the FACs well, even under changing conditions in the incoming IMF. Discrepancies exist between the modeled and observed current magnitudes. Notably, the winter Southern Hemisphere exhibits much lower current magnitudes overall. We also model a sharp transition of the location of magnetopause reconnection at the beginning of the interval, before the IMF remained northward for many hours. The reconnection location changed rapidly from a subsolar location at the low-latitude magnetopause under southward IMF conditions, to a high-latitude lobe reconnection location when the field is northward. This occurs during a fast rotation of the IMF at the shock front of a magnetic cloud.
| Type: | Article |
|---|---|
| Title: | Field-Aligned Current During an Interval of BY-Dominated Interplanetary-Field; Modeled-to-Observed Comparisons |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2021ja029722 |
| Publisher version: | https://doi.org/10.1029/2021JA029722 |
| Language: | English |
| Additional information: | ©2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Magnetosphere-ionosphere coupling, field-aligned currents, Aurora, modeling to observation comparison, polar cap phenomena |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10140554 |
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