Walker, S.N., Demekhov, A.G., Boardsen, S.A. et al. (3 more authors) (2016) Cluster observations of non-time-continuous magnetosonic waves. Journal of Geophysical Research: Space Physics, 121 (10). pp. 9701-9716. ISSN 2169-9402
Abstract
Equatorial magnetosonic waves are normally observed as temporally continuous sets of emissions lasting from minutes to hours. Recent observations, however, have shown that this is not always the case. Using Cluster data, this study identifies two distinct forms of these non-temporallycontinuous emissions. The first, referred to as rising tone emissions, are characterised by the systematic onset of wave activity at increasing proton gyroharmonic frequencies. Sets of harmonic emissions (emission elements) are observed to occur periodically in the region ±10◦ off the geomagnetic equator. The sweep rate of these emissions maximises at the geomagnetic equator. In addition, the ellipticity and propagation direction also change systematically as Cluster crosses the geomagnetic equator. It is shown that the observed frequency sweep rate is unlikely to result from the sideband instability related to nonlinear trapping of suprathermal protons in the wave field. The second form of emissions is characterised by the simultaneous onset of activity across a range of harmonic frequencies. These waves are observed at irregular intervals. Their occurrence correlates with changes in the spacecraft potential, a measurement that is used as a proxy for electron density
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016. The Authors. This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Automatic Control and Systems Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 17 Oct 2016 15:41 |
Last Modified: | 28 Feb 2017 16:28 |
Published Version: | http://dx.doi.org/10.1002/2016JA023287 |
Status: | Published |
Publisher: | American Geophysical Union (AGU) |
Refereed: | Yes |
Identification Number: | 10.1002/2016JA023287 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:106009 |
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