Link between premidnight second harmonic poloidal waves and auroral undulations
Abstract
We report, for the first time, an auroral undulation event on 1 May 2013 observed by an all-sky imager (ASI) at Athabasca (L = 4.6), Canada, for which in situ field and particle measurements in the conjugate magnetosphere were available from a Van Allen Probes spacecraft. The ASI observed a train of auroral undulation structures emerging in the pre-midnight subauroral ionosphere, during the growth phase of a substorm. The undulations propagated westward at a speed of 3-4 km s-1. The successive passage over an observing point yielded quasi-periodic oscillations in diffuse auroral emissions with a period of 40 s. In the conjugate magnetosphere the spacecraft encountered second harmonic poloidal ULF oscillations in the magnetic and electric fields. The field oscillations were accompanied by the corresponding oscillations in energetic particle fluxes. Most interestingly, both field and particle oscillations at the spacecraft had one-to-one association with the auroral luminosity oscillations around its footprint. Our findings strongly suggest that this auroral undulation event is closely linked to the generation of second harmonic poloidal waves.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMSM31A2443M
- Keywords:
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- 6939 Magnetospheric physics;
- RADIO SCIENCEDE: 7845 Particle acceleration;
- SPACE PLASMA PHYSICSDE: 7867 Wave/particle interactions;
- SPACE PLASMA PHYSICSDE: 7959 Models;
- SPACE WEATHER