Determination of the Ionospheric Convection Pattern from DMSP Data

1988 ◽  
Author(s):  
Marc R. Hairston ◽  
Roderick A. Heelis
Nature ◽  
1985 ◽  
Vol 316 (6024) ◽  
pp. 133-135 ◽  
Author(s):  
M. D. Burrage ◽  
J. A. Waldock ◽  
T. B. Jones ◽  
E. Nielsen

2009 ◽  
Vol 27 (8) ◽  
pp. 3077-3087 ◽  
Author(s):  
M. Förster ◽  
Y. I. Feldstein ◽  
S. E. Haaland ◽  
L. A. Dremukhina ◽  
L. I. Gromova ◽  
...  

Abstract. Cluster/EDI electron drift observations above the Northern and Southern polar cap areas for more than seven and a half years (2001–2008) have been used to derive a statistical model of the high-latitude electric potential distribution for summer conditions. Based on potential pattern for different orientations of the interplanetary magnetic field (IMF) in the GSM y-z-plane, basic convection pattern (BCP) were derived, that represent the main characteristics of the electric potential distribution in dependence on the IMF. The BCPs comprise the IMF-independent potential distribution as well as patterns, which describe the dependence on positive and negative IMFBz and IMFBy variations. The full set of BCPs allows to describe the spatial and temporal variation of the high-latitude electric potential (ionospheric convection) for any solar wind IMF condition near the Earth's magnetopause within reasonable ranges. The comparison of the Cluster/EDI model with the IZMEM ionospheric convection model, which was derived from ground-based magnetometer observations, shows a good agreement of the basic patterns and its variation with the IMF. According to the statistical models, there is a two-cell antisunward convection within the polar cap for northward IMFBz+≤2 nT, while for increasing northward IMFBz+ there appears a region of sunward convection within the high-latitude daytime sector, which assumes the form of two additional cells with sunward convection between them for IMFBz+≈4–5 nT. This results in a four-cell convection pattern of the high-latitude convection. In dependence of the ±IMFBy contribution during sufficiently strong northward IMFBz conditions, a transformation to three-cell convection patterns takes place.


1994 ◽  
Vol 12 (12) ◽  
pp. 1174-1191 ◽  
Author(s):  
J. R. Taylor ◽  
T. K. Yeoman ◽  
M. Lester ◽  
M. J. Buonsanto ◽  
J. L. Scali ◽  
...  

Abstract. We report on the response of high-latitude ionospheric convection during the magnetic storm of March 20-21 1990. IMP-8 measurements of solar wind plasma and interplanetary magnetic field (IMF), ionospheric convection flow measurements from the Wick and Goose Bay coherent radars, EISCAT, Millstone Hill and Sondrestrom incoherent radars and three digisondes at Millstone Hill, Goose Bay and Qaanaaq are presented. Two intervals of particular interest have been identified. The first starts with a storm sudden commencement at 2243 UT on March 20 and includes the ionospheric activity in the following 7 h. The response time of the ionospheric convection to the southward turning of the IMF in the dusk to midnight local times is found to be approximately half that measured in a similar study at comparable local times during more normal solar wind conditions. Furthermore, this response time is the same as those previously measured on the dayside. An investigation of the expansion of the polar cap during a substorm growth phase based on Faraday's law suggests that the expansion of the polar cap was nonuniform. A subsequent reconfiguration of the nightside convection pattern was also observed, although it was not possible to distinguish between effects due to possible changes in By and effects due to substorm activity. The second interval, 1200-2100 UT 21 March 1990, included a southward turning of the IMF which resulted in the Bz component becoming -10 nT. The response time on the dayside to this change in the IMF at the magnetopause was approximately 15 min to 30 min which is a factor of ~2 greater than those previously measured at higher latitudes. A movement of the nightside flow reversal, possibly driven by current systems associated with the substorm expansion phases, was observed, implying that the nightside convection pattern can be dominated by substorm activity.


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