Journal ArticleDOI
Observations of an enhanced convection channel in the cusp ionosphere
Michael Pinnock,Alan S. Rodger,J. R. Dudeney,K. B. Baker,Patrick T. Newell,R. A. Greenwald,M. E. Greenspan +6 more
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TLDR
In this paper, the authors describe combined observations by the PACE HF backscatter radar and the DMSP F9 polar-orbiting satellite of a transient velocity signature in the southern hemisphere ionospheric cusp.Abstract:
Transient or patchy magnetic field line merging on the dayside magnetopause, giving rise to flux transfer events (FTEs), is thought to play a significant role in energizing high-latitude ionospheric convection during periods of southward interplanetary magnetic field. Several transient velocity patterns in the cusp ionosphere have been presented as candidate FTE signatures. Instrument limitations, combined with uncertainties about the magnetopause processes causing individual velocity transients, mean that definitive observations of the ionospheric signature of FTEs have yet to be presented. This paper describes combined observations by the PACE HF backscatter radar and the DMSP F9 polar-orbiting satellite of a transient velocity signature in the southern hemisphere ionospheric cusp. The prevailing solar wind conditions suggest that it is the result of enhanced magnetic merging at the magnetopause. The satellite particle precipitation data associated with the transient are typically cusplike in nature. The presence of spatially discrete patches of accelerated ions at the equatorward edge of the cusp is consistent with the ion acceleration that could occur with merging. The combined radar line-of-sight velocity data and the satellite transverse plasma drift data are consistent with a channel of enhanced convection superposed on the ambient cusp plasma flow. This channel is at least 900 km in longitudinal extent but only 100 km wide. It is zonally aligned for most of its extent, except at the western limit where it rotates sharply poleward. Weak return flow is observed outside the channel. These observations are compared with and contrasted to similar events seen by the EISCAT radar and by optical instruments.read more
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Journal ArticleDOI
Initial development of HF radar polar patch caused by azimuthal flow burst in the cusp
TL;DR: In this article, the authors investigated the relationship between the initial development of a poleward propagating feature of the radar backscatter and a fast azimuthal flow in the cusp.
Journal ArticleDOI
Reversed flow events in the cusp ionosphere detected by SuperDARN HF radars
Kjellmar Oksavik,Kjellmar Oksavik,Joran Moen,Joran Moen,E. H. Rekaa,H. C. Carlson,Mark Lester +6 more
TL;DR: In this article, it was shown that coherent scatter Super Dual Auroral Radar Network (SuperDARN) HF radars can also see RFEs, which are 100-200 km wide flow channels opposing the background plasma convection.
Electron Density Enhancements in the Polar Cap During Periods of Dayside Reconnection
TL;DR: In this article, the authors monitor the location of the region 1 current oval which is related to the position of the polar cap boundary (PCB) and identify intervals when the current oval and hence the PCB moved equatorward for extended periods lasting at least 75 min.
Journal ArticleDOI
Plasma flow during the brightening of proton aurora in the cusp
Satoshi Taguchi,Keisuke Hosokawa,Shin Suzuki,A. Tawara,Harald U. Frey,Jürgen Matzka,Akira Sessai Yukimatu,Noriaki K. Sato +7 more
TL;DR: In this article, the authors present the characteristics of plasma flow during a westward moving proton aurora in the cusp, observed on 28 July 2000, using data from the Super Dual Auroral Radar Network (SuperDARN), the far ultraviolet instrument on the IMAGE spacecraft, and a magnetometer installed on the east coast of Greenland.
Dissertation
On the flow shear instability driven by Reversed Flow Events in the polar ionosphere
TL;DR: In this article, the authors quantified the growth rate of the Kelvin-Helmholtz instability in the shear regions of Reversed Flow Events using a multi-instrument dataset consisting of coherent and incoherent scatter radar data, as well as in-situ rocket measurements.
References
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Journal ArticleDOI
Empirical high-latitude electric field models
J. P. Heppner,N. C. Maynard +1 more
TL;DR: In this paper, large-scale revisions of the OGO 6 dawn-dusk measurement models are made, showing that the deformations of the two-cell patterns lead to sunward convection in dayside polar regions, while maintaining the integrity of the night-side convection pattern.
Journal ArticleDOI
The cusp and the cleft/boundary layer: Low-altitude identification and statistical local time variation
Patrick T. Newell,Ching-I. Meng +1 more
TL;DR: In this paper, the authors investigated the distinction between the low-altitude cusp and the cleft (with the latter identified as the ionospheric signature of low-latitude boundary layer (LLBL)) on both a statistical and a case study basis.
Journal ArticleDOI
Ionospheric traveling convection vortices observed near the polar cleft: A triggered response to sudden changes in the solar wind
TL;DR: In this paper, the signatures of localized ionospheric traveling convection vortices were analyzed using 20-second resolution magnetometer data from an array of temporary stations operated around Sondre Stromfjord, Greenland during the summer of 1986.
Journal ArticleDOI
What are flux transfer events
TL;DR: In this paper, the authors argue that surges in the reconnection rate on the magnetopause give rise to bubble-like regions of plasma containing a twisted field with energetic streaming particles in the outer layers.
Journal ArticleDOI
Magnetic flux transfer at the magnetopause based on single X line bursty reconnection
TL;DR: In this paper, a model of flux transfer events at the dayside magnetopause is proposed, which is based on non-stationary reconnection along a single X line over a large longitudinal segment.