Rae, IJ;
Watt, CEJ;
Rae, I;
(2016)
ULF Waves above the Nightside Auroral Oval during Substorm Onset.
In: Keiling, A and Lee, D-H and Nakariakov, V, (eds.)
Low-Frequency Waves in Space Plasmas.
(pp. 99-120).
American Geophysical Union
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Abstract
This chapter reviews historical ground-based observations of ultra-low-frequency (ULF) waves tied to substorms, and highlights new research linking these ULF waves explicitly to substorm onset itself. There are several robust methods that can be used to determine the characteristics of a nonstationary time series such as the ULF magnetic field traces observed in the auroral zone during substorms. These include the pure state filter, the Hilbert-Huang transform, and wavelet analysis. The first indication of a substorm is a sudden brightening of one of the quiet arcs lying in the midnight sector of the oval. The chapter focuses on the properties of ULF waves that are seen in two-dimensional images of auroral intensity near substorm expansion phase onset. It also discusses a wider range of magnetotail instabilities that could be responsible for the azimuthally structured auroral forms at substorm onset.
Type: | Book chapter |
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Title: | ULF Waves above the Nightside Auroral Oval during Substorm Onset |
ISBN: | 1119054958 |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1002/9781119055006 |
Publisher version: | http://onlinelibrary.wiley.com/book/10.1002/978111... |
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: | Azimuthally structured auroral forms; Hilbert-Huang transform; magnetotail instabilities; nightside auroral oval; nonstationary time series; pure state filter; substorm onset; ultra-low-frequency waves; wavelet analysis |
UCL classification: | UCL UCL > Provost and Vice Provost Offices 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/1503372 |
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