Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars
[1] We present several examples of reversed flow events (RFEs) from the cusp ionosphere. RFEs are 100–200 km wide flow channels opposing the background plasma convection. RFEs were discovered a few years ago by the incoherent scatter European Incoherent Scatter Svalbard Radar. In this paper we show...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.463.378 2023-05-15T18:29:48+02:00 Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars K. Oksavik The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.463.378 http://folk.uib.no/st07350/papers/oksavik2011JA016788.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.463.378 http://folk.uib.no/st07350/papers/oksavik2011JA016788.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://folk.uib.no/st07350/papers/oksavik2011JA016788.pdf text ftciteseerx 2016-01-08T06:45:16Z [1] We present several examples of reversed flow events (RFEs) from the cusp ionosphere. RFEs are 100–200 km wide flow channels opposing the background plasma convection. RFEs were discovered a few years ago by the incoherent scatter European Incoherent Scatter Svalbard Radar. In this paper we show that coherent scatter Super Dual Auroral Radar Network (SuperDARN) HF radars can also see RFEs. We report a close relationship between RFEs and the development of HF backscatter power and spectral width. Wide spectra were seen near the edges of the RFEs (i.e., associated with the flow shear), and there was a significant increase in SuperDARN HF backscatter power when the RFE expanded. This increase in power is much faster than anticipated from the gradient drift instability alone, supporting the hypothesis that RFE flow shears foster rapid growth of Kelvin-Helmholtz instabilities. That decameter-scale irregularities form so rapidly should be an important guide to the development of instability theory for cascade of plasma irregularities from larger to smaller scale sizes. Text Svalbard Unknown Svalbard |
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[1] We present several examples of reversed flow events (RFEs) from the cusp ionosphere. RFEs are 100–200 km wide flow channels opposing the background plasma convection. RFEs were discovered a few years ago by the incoherent scatter European Incoherent Scatter Svalbard Radar. In this paper we show that coherent scatter Super Dual Auroral Radar Network (SuperDARN) HF radars can also see RFEs. We report a close relationship between RFEs and the development of HF backscatter power and spectral width. Wide spectra were seen near the edges of the RFEs (i.e., associated with the flow shear), and there was a significant increase in SuperDARN HF backscatter power when the RFE expanded. This increase in power is much faster than anticipated from the gradient drift instability alone, supporting the hypothesis that RFE flow shears foster rapid growth of Kelvin-Helmholtz instabilities. That decameter-scale irregularities form so rapidly should be an important guide to the development of instability theory for cascade of plasma irregularities from larger to smaller scale sizes. |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
K. Oksavik |
spellingShingle |
K. Oksavik Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars |
author_facet |
K. Oksavik |
author_sort |
K. Oksavik |
title |
Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars |
title_short |
Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars |
title_full |
Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars |
title_fullStr |
Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars |
title_full_unstemmed |
Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars |
title_sort |
reversed flow events in the cusp ionosphere detected by superdarn hf radars |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.463.378 http://folk.uib.no/st07350/papers/oksavik2011JA016788.pdf |
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Svalbard |
geographic_facet |
Svalbard |
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Svalbard |
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Svalbard |
op_source |
http://folk.uib.no/st07350/papers/oksavik2011JA016788.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.463.378 http://folk.uib.no/st07350/papers/oksavik2011JA016788.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766213177321717760 |