Rae, IJ;
Murphy, KR;
Watt, CEJ;
Sandhu, JK;
Georgiou, M;
Degeling, AW;
Forsyth, C;
... Shi, Q; + view all
(2019)
How do Ultra‐Low Frequency waves access the inner magnetosphere during geomagnetic storms?
Geophysical Research Letters
, 46
(19)
pp. 10699-10709.
10.1029/2019gl082395.
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Abstract
Wave‐particle interactions play a key role in radiation belt dynamics. Traditionally, Ultra‐Low Frequency (ULF) wave‐particle interaction is parameterised statistically by a small number of controlling factors for given solar wind driving conditions or geomagnetic activity levels. Here, we investigate solar wind driving of ultra‐low frequency (ULF) wave power and the role of the magnetosphere in screening that power from penetrating deep into the inner magnetosphere. We demonstrate that, during enhanced ring current intensity, the Alfvén continuum plummets, allowing lower frequency waves to penetrate deeper into the magnetosphere than during quiet periods. With this penetration, ULF wave power is able to accumulate closer to the Earth than characterised by statistical models. During periods of enhanced solar wind driving such as coronal mass ejection driven storms, where ring current intensities maximise, the observed penetration provides a simple physics‐based reason for why storm‐time ULF wave power is different compared to non‐storm time waves.
| Type: | Article |
|---|---|
| Title: | How do Ultra‐Low Frequency waves access the inner magnetosphere during geomagnetic storms? |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2019gl082395 |
| Publisher version: | https://doi.org/10.1029/2019GL082395 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | ULF waves, storm‐time, radiation belt, wave penetration |
| 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/10079543 |
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