Low-altitude ionization and Pedersen conductivity layer associated with energetic electron precipitaiton
Abstract
Pulsating aurora usually manifests the energy deposits from the magnetosphere, particularly by energetic electron precipitation, thus is important for understanding the magnetosphere-ionosphere couplings. In this study, a CIR-driven storm event is investigated during which pulsating aurora is detected by 3 ground-based all-sky imagers in Scandinavian sector (at Sodankyla and Kevo in Finland, and at Kiruna in Sweden) continuously for a few hours on the nightside. European Incoherent SCATer (EISCAT) radar observations revealed significantly enhanced ionization down to 80 km in the ionosphere. NOAA/POES satellites simultaneously observed energetic electron precipitation (>30 keV), suggesting the relationship between incident energetic precipitation and the low-altitude ionization. Global simulations demonstrate that incident electrons with E > 30 keV scattered by chorus waves from the magnetosphere are responsible for the energization in the low-altitude ionosphere. It creates a secondary Pedersen conductivity layer around 80 km, in addition to the primary one at 120 km, which confirms the similar phenomena in observations. The extra conductivity layer at low altitude may promote the energy dissipation in the ionosphere due to elevated conductance. It may also change the traditional paradigm of current closure at the E-layer to extend further down to the D-layer.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSM43A..01Y
- Keywords:
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- 2431 Ionosphere/magnetosphere interactions;
- IONOSPHEREDE: 2475 Polar cap ionosphere;
- IONOSPHEREDE: 2721 Field-aligned currents and current systems;
- MAGNETOSPHERIC PHYSICSDE: 2736 Magnetosphere/ionosphere interactions;
- MAGNETOSPHERIC PHYSICS;
- 2431 Ionosphere/magnetosphere interactions;
- IONOSPHEREDE: 2475 Polar cap ionosphere;
- IONOSPHEREDE: 2721 Field-aligned currents and current systems;
- MAGNETOSPHERIC PHYSICSDE: 2736 Magnetosphere/ionosphere interactions;
- MAGNETOSPHERIC PHYSICS