A 2-D comparison of ionospheric convection derived from SuperDARN and DMSP measurements

Xu, Liang; Koustov, A. V.; Xu, Jisheng; Drayton, R. A.; Huo, Lili

doi:10.1016/j.asr.2007.06.044

Cited by 18 publications

(18 citation statements)

References 12 publications

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“…We interpret their data to have a saturation onset at around 3–5 mV/m for IMF due north. Their study does suggest a lower saturation level (20 kV), however a quantitative discrepancy is not unexpected as previous satellite measurements of the reverse convection potential have given values up to the order of 60–70 kV [ Taguchi and Hoffman , 1995], and comparative studies of convection velocities have shown SuperDARN to give lower values in general compared to DMSP [ Drayton et al , 2005; Xu et al , 2008].…”

Section: Discussionmentioning

confidence: 86%

Reverse convection potential: A statistical study of the general properties of lobe reconnection and saturation effects during northward IMF

2009

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[1] The saturation tendency of the cross-polar potential for southward interplanetary magnetic fields (IMFs) has been the subject of numerous studies; however, the behavior of the reverse convection potential when the IMF is northward remains less clear. In this study, we present a thorough statistical analysis of the four-cell convection pattern associated with northward IMF and lobe reconnection based on a large set of DMSP F13 satellite data. Results show a behavior much similar to the southward IMF case, with a clear saturation tendency of the reverse convection potential for strong solar wind electric fields both seen in the data and validated in the statistical analysis. The saturated potential level reaches a limit of about 60 kV, on the order of a fourth of the saturated potential seen for dayside reconnection during southward IMF.

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Section: Discussionmentioning

confidence: 86%

Reverse convection potential: A statistical study of the general properties of lobe reconnection and saturation effects during northward IMF

2009

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“…In the past, this has been explained by the fact that the polar cap expands equatorward during increasingly strong driving, which could mean that the potential pattern is outside the SuperDARN radars' fields of view [ Hairston et al , 2005]. Recent studies, however, have compared line of site velocity vectors measured by SuperDARN with DMSP cross‐track plasma drift measurements and shown that the velocities measured by SuperDARN are 0.3 to 0.7 times smaller than those measured by DMSP [ Drayton et al , 2005; Xu et al , 2007]. Sundberg et al [2009] showed saturation of Φ RC using DMSP and also demonstrated it to occur at approximately one fourth the saturation Φ PC under southward IMF observed by Hairston et al [2005].…”

Section: Methodsmentioning

confidence: 99%

Reverse convection potential saturation during northward IMF under various driving conditions

2009

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[1] We report the results of an investigation of the reverse convection potentials in the dayside high-latitude ionosphere during periods of steady northward interplanetary magnetic field (IMF). While it has been demonstrated that the reverse convection potentials exhibit saturation behavior, an investigation into how the saturated reverse convection cells respond to various driving conditions has not yet been performed. We use the OMNI database from 1998 to 2007 to search for events in solar wind data propagated to the bow shock when the IMF is northward and when various driving parameters are stable for more than 40 min. We then use bin-averaged SuperDARN Doppler radar velocity data to apply a spherical harmonic fit to calculate the average potential pattern for various driving conditions. Results show that the saturated reverse convection potential during northward IMF is substantially lower than during southward IMF (as expected), but the strength of the saturation electric field at a particular location is comparable during northward IMF to what it is during southward IMF. Seasonal dependence and dependence on the Alfvènic Mach number and solar wind b are also investigated. It appears that the reverse convection potential demonstrates the opposite of what is expected for seasonal dependence, and that the Alfvènic Mach number is not the fundamental driver of its saturation.

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“…The effect is clearly detectable at large drifts of >1 km/s. Xu et al (2008) statistically compared the DMSP velocity vectors and SuperDARN-inferred convection vectors and showed that the radar velocities are typically smaller than the DMSP ones. Several explanations for the differences have been proposed, including the fact that temporal and spatial resolution of the instruments is not the same.…”

Section: Discussionmentioning

confidence: 99%

On the SuperDARN cross polar cap potential saturation effect

et al. 2009

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Abstract. Variation of the cross polar cap potential (CPCP) with the interplanetary electric field (IEF), the merging electric field E KL , the Polar Cap North (PCN) magnetic index, and the solar wind-magnetosphere coupling function E C of Newell et al. (2007) is investigated by considering convection data collected by the Super Dual Auroral Radar Network (SuperDARN) in the Northern Hemisphere. Winter and summer observations are considered separately. All variations considered show close to linear trend at small values of the parameters and tendency for the saturation at large values. The threshold values starting from which the non-linearity was evident were estimated to be IEF*∼E * KL ∼3 mV/m, PCN*∼3-4, and E * C ∼1.5×10 4 . The data indicate that saturation starts at larger values of the above parameters and reaches larger (up to 10 kV) saturation levels during summer. Conclusions are supported by a limited data set of simultaneous SuperDARN observations in the Northern (summer) and Southern (winter) Hemispheres. It is argued that the SuperDARN CPCP saturation levels and the thresholds for the non-linearity to be seen are affected by the method of the CPCP estimates.

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A 2-D comparison of ionospheric convection derived from SuperDARN and DMSP measurements

Cited by 18 publications

References 12 publications

Reverse convection potential: A statistical study of the general properties of lobe reconnection and saturation effects during northward IMF

Reverse convection potential: A statistical study of the general properties of lobe reconnection and saturation effects during northward IMF

Reverse convection potential saturation during northward IMF under various driving conditions

On the SuperDARN cross polar cap potential saturation effect

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