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- Title
A statistical survey of heat input parameters into the cusp thermosphere.
- Authors
Skjæveland, Åsmund Steen; Carlson, Herbert C.; Moen, Jøran Idar
- Abstract
Based on three winters of observational data, we present those ionosphere parameters deemed most critical to realistic space weather ionosphere and thermosphere representation and prediction, in regions impacted by variability in the cusp. The CHAMP spacecraft revealed large variability in cusp thermosphere densities, measuring frequent satellite drag enhancements, up to doublings. The community recognizes a clear need for more realistic representation of plasma flows and electron densities near the cusp. Existing average value models produce order of magnitude errors in these parameters, resulting in large underestimations of predicted drag. We fill this knowledge gap with statistics-based specification of these key parameters over their range of observed values. The European Incoherent Scatter Svalbard Radar tracks plasma flow V i, electron density N e, and electron, ion temperatures T e, T i, with consecutive 2-3 min windshield wipe scans of 1000 × 500 km areas. This allows mapping the maximum T i of a large area within or near the cusp with high temporal resolution. In magnetic field-aligned mode the radar can measure high-resolution profiles of these plasma parameters. By deriving statistics for N e and T i, we enable derivation of thermosphere heating deposition under background and frictional drag-dominated magnetic reconnection conditions. We separate our N e and T i profiles into quiescent and enhanced states, which are not closely correlated due to the spatial structure of the reconnection foot point. Use of our data-based parameter inputs can make order of magnitude corrections to input data driving thermosphere models, enabling removal of previous twofold drag errors.
- Publication
Journal of Geophysical Research. Space Physics, 2017, Vol 122, Issue 9, p9622
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1002/2016JA023594