Alfvénic Dynamics and Fine Structuring of Discrete Auroral Arcs: Swarm and e-POP Observations
Abstract
The electrodynamics associated with dual discrete arc aurora with anti-parallel flow along the arcs were observed nearly simultaneously by the enhanced Polar Outflow Probe (e-POP) and the Swarm A and C spacecraft. Auroral imaging from e-POP reveal 1-10 km structuring of the arcs, which move and evolve on second timescales and confound the traditional single-spacecraft field-aligned current algorithms. High-cadence magnetic data from e-POP shows 1-10 Hz, presumably Alfvénic perturbations co-incident with and at the same scale size as the observed dynamic auroral fine structures. High-cadence electric and magnetic field data from Swarm A reveals non-stationary electrodynamics involving reflected and interfering Alfvén waves and signatures of modulation consistent with trapping in the Ionospheric Alfvén Resonator (IAR). Together, these observations suggest a role for Alfven waves, perhaps also the IAR, in discrete arc dynamics on 0.2 - 10s timescales and 1-10 km spatial scales.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMSM41A2675M
- Keywords:
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- 2427 Ionosphere/atmosphere interactions;
- IONOSPHERE;
- 2704 Auroral phenomena;
- MAGNETOSPHERIC PHYSICS;
- 2721 Field-aligned currents and current systems;
- MAGNETOSPHERIC PHYSICS;
- 2736 Magnetosphere/ionosphere interactions;
- MAGNETOSPHERIC PHYSICS