scholarly journals Effects of the solar wind electric field and ionospheric conductance on the cross polar cap potential: Results of global MHD modeling

2003 ◽  
Vol 30 (23) ◽  
pp. n/a-n/a ◽  
Author(s):  
V. G. Merkine ◽  
K. Papadopoulos ◽  
G. Milikh ◽  
A. S. Sharma ◽  
X. Shao ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Polar Cap ◽  
Mhd Modeling ◽  
The Cross ◽  
Cross Polar Cap Potential

scholarly journals Predicted dependence of the cross polar cap potential saturation on the type of solar wind stream

2015 ◽  
Vol 56 (7) ◽  
pp. 1366-1373 ◽  
Author(s):  
Nadezhda Nikolaeva ◽  
Yuri Yermolaev ◽  
Irina Lodkina
Keyword(s):  
Solar Wind ◽  
Solar Wind Stream ◽  
Polar Cap ◽  
The Cross ◽  
Cross Polar Cap Potential

scholarly journals A new formulation for the ionospheric cross polar cap potential including saturation effects

2005 ◽  
Vol 23 (11) ◽  
pp. 3533-3547 ◽  
Author(s):  
A. J. Ridley
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Mach Number ◽  
Interplanetary Magnetic Field ◽  
Polar Cap ◽  
Pressure Balance ◽  
Simple Modification ◽  
Post Shock ◽  
Cross Polar Cap Potential ◽  
New Formulation

Abstract. It is known that the ionospheric cross polar cap potential (CPCP) saturates when the interplanetary magnetic field (IMF) Bz becomes very large. Few studies have offered physical explanations as to why the polar cap potential saturates. We present 13 events in which the reconnection electric field (REF) goes above 12mV/m at some time. When these events are examined as typically done in previous studies, all of them show some signs of saturation (i.e., over-prediction of the CPCP based on a linear relationship between the IMF and the CPCP). We show that by taking into account the size of the magnetosphere and the fact that the post-shock magnetic field strength is strongly dependent upon the solar wind Mach number, we can better specify the ionospheric CPCP. The CPCP (Φ) can be expressed as Φ=(10-4v2+11.7B(1-e-Ma/3)sin3(θ/2)) {rms/9 (where v is the solar wind velocity, B is the combined Y and Z components of the interplanetary magnetic field, Ma is the solar wind Mach number, θ=acos(Bz/B), and rms is the stand-off distance to the magnetopause, assuming pressure-balance between the solar wind and the magnetosphere). This is a simple modification of the original Boyle et al. (1997) formulation.

scholarly journals Dayside and nightside contributions to the cross polar cap potential: placing an upper limit on a viscous-like interaction

2004 ◽  
Vol 22 (10) ◽  
pp. 3771-3777 ◽  
Author(s):  
S. E. Milan
Keyword(s):  
Magnetic Flux ◽  
Polar Regions ◽  
Polar Cap ◽  
Average Decrease ◽  
The Past ◽  
Viscous Interaction ◽  
The North ◽  
Upper Limit ◽  
The Cross ◽  
Cross Polar Cap Potential

Abstract. Observations of changes in size of the ionospheric polar cap allow the dayside and nightside reconnection rates to be quantified. From these it is straightforward to estimate the rate of antisunward transport of magnetic flux across the polar regions, quantified by the cross polar cap potential ΦPC. When correlated with upstream measurements of the north-south component of the IMF, ΦPC is found to increase for more negative Bz, as expected. However, we also find that ΦPC does not, on average, decrease to zero, even for strongly northward IMF. In the past this has been interpreted as evidence for a viscous interaction between the magnetosheath flow and the outer boundaries of the magnetosphere. In contrast, we show that this is the consequence of flows excited by tail reconnection, which is inherently uncorrelated with IMF Bz.

scholarly journals On the SuperDARN cross polar cap potential saturation effect

2009 ◽  
Vol 27 (10) ◽  
pp. 3755-3764 ◽  
Author(s):  
A. V. Koustov ◽  
G. Ya. Khachikjan ◽  
R. A. Makarevich ◽  
C. Bryant
Keyword(s):  
Electric Field ◽  
Linear Trend ◽  
Limited Data ◽  
Polar Cap ◽  
Data Set ◽  
Northern Summer ◽  
Radar Network ◽  
Cross Polar Cap Potential ◽  
Hemisphere Winter ◽  
Magnetic Index

Abstract. Variation of the cross polar cap potential (CPCP) with the interplanetary electric field (IEF), the merging electric field EKL, the Polar Cap North (PCN) magnetic index, and the solar wind-magnetosphere coupling function EC 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*~EKL*~3 mV/m, PCN*~3–4, and EC*~1.5×104. 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.

scholarly journals Statistical study of the subauroral polarization stream: Its dependence on the cross-polar cap potential and subauroral conductance

2008 ◽  
Vol 113 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
Hui Wang ◽  
Aaron J. Ridley ◽  
Hermann Lühr ◽  
Michael W. Liemohn ◽  
Shu Y. Ma
Keyword(s):  
Statistical Study ◽  
Polar Cap ◽  
The Cross ◽  
Cross Polar Cap Potential
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