An examination of the source of decameter-scale irregularities in the geomagnetically disturbed mid-latitude ionosphere

TitleAn examination of the source of decameter-scale irregularities in the geomagnetically disturbed mid-latitude ionosphere
Publication TypeConference Paper
Year of Publication2014
AuthorsThomas, EG, Yan, J, Zhang, J, Baker, JBH, J. Ruohoniemi, M, Hoskawa, K, Erickson, PJ, Coster, AJ, Foster, JC
Conference Name2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS)2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS)
Date Published08/2014
PublisherIEEE
Conference LocationBeijing, China
KeywordsIonosphere; Plasmas; SUPERDARN; Van Allen Probes
AbstractWe present first results from a study of the plasma instability mechanism responsible for the small-scale (∼10 m) ionospheric density irregularities commonly observed by the Super Dual Auroral Radar Network (SuperDARN) HF radars in the vicinity of Sub Auroral Polarization Streams (SAPS) during periods of geomagnetic disturbance. A focus is placed on the mid-latitude region of the ionosphere over North America where recent expansion of the SuperDARN network allows for extensive direct comparisons with total electron content (TEC) measurements from a dense network of ground-based GPS receivers. The TEC observations indicate that high-speed SAPS channels and the associated small-scale irregularities are typically located within the mid-latitude ionospheric trough. The Millstone Hill Incoherent Scatter Radar (ISR), operating in campaign mode in support of the NASA Van Allen Probes mission, provided measurements of F region ion/electron density, velocity, and temperature suitable for identifying potential mechanisms of plasma instability during a SAPS event that extended over 12 hours of magnetic local time (MLT) on 2 February 2013. Previous work has indicated that the density gradients associated with the poleward wall of the mid-latitude trough can produce small-scale irregularities due to the gradient drift instability during quiet periods by cascade from larger-scale structures. In this study we demonstrate that the gradient drift instability is a viable source for the direct generation of the small-scale irregularities observed by SuperDARN radars in the mid-latitude ionosphere during geomagnetically disturbed conditions.
URLhttp://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929853
DOI10.1109/URSIGASS.2014.6929853


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