Identifying STEVE's magnetospheric driver using conjugate observations in the magnetosphere and on the ground
Abstract
In this study, we have identified the magnetospheric driver of STEVE using conjugate observations when the Van Allen Probes' footprint directly crossed both STEVE and a stable red aurora (SAR) arc. In the ionosphere, STEVE is found to be associated with subauroral ion drift (SAID) features, including electron temperature peak, density gradient, and westward ion flow. The SAR arc at lower latitudes corresponds to regions inside the plasmapause with isotropic plasma heating, which causes redline-only SAR emission via heat conduction. STEVE corresponds to the sharp plasmapause boundary containing quasi-static SAID electric field and parallel electrons accelerated by kinetic Alfven waves. These parallel electrons can precipitate and be further accelerated via auroral acceleration processes powered by Alfven waves propagating along the magnetic field with the plasmapause as a waveguide. This electron precipitation, superimposed on the heat conduction, could explain multi-wavelength continuous STEVE emission. The green picket-fence emissions are likely optical manifestations of electron precipitation associated with wave structures traveling along the plasmapause.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM22A..02C
- Keywords:
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- 0310 Airglow and aurora;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 2704 Auroral phenomena;
- MAGNETOSPHERIC PHYSICS;
- 2716 Energetic particles: precipitating;
- MAGNETOSPHERIC PHYSICS;
- 2772 Plasma waves and instabilities;
- MAGNETOSPHERIC PHYSICS