Rae, IJ;
Murphy, KR;
Watt, CEJ;
Rostoker, G;
Rankin, R;
Mann, IR;
Hodgson, CR;
... Forsyth, C; + view all
(2014)
Field line resonances as a trigger and a tracer for substorm onset.
Journal of Geophysical Research: Space Physics
, 119
(7)
pp. 5343-5363.
10.1002/2013JA018889.
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Abstract
In this paper, we show that periodic auroral arc structures are seen at the location of one particular auroral substorm onset for the 15 min preceding onset, suggesting that field line resonances should be considered a strong candidate for triggering substorm onset. Irrespective of whether this field line resonance is coincidentally or causally linked to this substorm onset, the characteristics of the field line resonance can be used to remote sense the characteristics of the geomagnetic field line that supports substorm onset. In this instance, the eigenfrequency of this resonance is around 12 mHz. Interestingly, however, there is no evidence of this field line resonance in a seven satellite major Time History of Events and Macroscale Interactions during Substorms (THEMIS)-GOES conjunction, ranging from geosynchronous orbit to ~30 RE. However, using space-based cross-phase measurements of the local field line eigenfrequency at the inner THEMIS locations, we find that the local field line eigenfrequency is 6-10 mHz. Hence, we can reliably say that this 12 mHz Field Line Resonance (FLR) must lie inside of THEMIS locations. Our conclusion is that a high-m field line resonance can both represent a strong candidate for a trigger for substorm onset, as first proposed by Samson et al. (1992), and that its characteristics can provide invaluable information as to where substorm onset occurs in the magnetosphere.
| Type: | Article |
|---|---|
| Title: | Field line resonances as a trigger and a tracer for substorm onset |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/2013JA018889 |
| Publisher version: | http://dx.doi.org/10.1002/2013JA018889 |
| Language: | English |
| Additional information: | Copyright © 2014 The Authors. This is an open access article under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| 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/1435443 |
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