High-latitude plasma convection from Cluster EDI measurements: method and IMF-dependence - Haaland, S. E.; Paschmann, G.; Förster, M.; Quinn, J. M.; Torbert, R. B.; McIlwain, C. E.; Vaith, H.; Puhl-Quinn, P. A.; Kletzing, C. A. (Ann. Geophys., 2007)