Ground Magnetic Perturbations in the Polar Cap and Cleft: Relationship with the IMF
Average empirical models of the magnetospheric and ionospheric electrodynamic parameters play an important role as a frame of reference and also as boundary conditions for the more advanced dynamical models. Furthermore the empirical models may be used to test our physical models and concepts. With the vast amount of geophysical and solar data which is now available, a number of empirical models have appeared, but the different empirical models are not all comparable due to a difference in experimental methods, averaging techniques, and observing conditions. In this review we will describe various average models of electric fields and currents and compare them with models obtained using ground-based magnetometer measurements. It is our conclusion that the major differences between the models are not primarily due to the different measuring techniques, but can be explained taking the merits and demerits of the different averaging and normalization techniques into consideration. This is important to take into account when trying to understand the physics, which the empirical models represent.
KeywordsSolar Wind Interplanetary Magnetic Field Magnetic Local Time Convection Pattern Electric Potential Distribution
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- Foster, J. C., Holt, J. M., Musgrove, R. G., and Evans, D. S. (1986) ‘Solar wind dependencies of high-latitude convection and precipitation’, in Y. Kamide and J. A. Slavin, eds., Solar Wind -Magnetosphere Coupling, Terra, Tokyo, pp. 477–494.Google Scholar
- Friis-Christensen, E. (1979) ‘The effect of the IMF on convection patterns and equivalent currents in the polar cap and cusp’, Magneto spheric Study 1979, Japanese IMS Committee, 290–293.Google Scholar
- Friis-Christensen, E. (1986) ‘Solar wind control of the polar cusp’, in Y. Kamide and J. A. Slavin, eds., Solar Wind-Magnetosphere Coupling, Terra, Tokyo, pp. 423–440.Google Scholar
- Friis-Christensen, E.(1989) ‘Ground magnetic perturbations in the polar cap and cleft: Structure and dynamics of ionospheric currents’, this volume.Google Scholar
- Friis-Christensen, E. and Lassen, K. (1989) ‘Large scale distribution of discrete auroras and field- aligned currents’, presented at the International Conference on Auroral Physics, Cambridge July 10–15, 1988.Google Scholar
- Marklund, G. T., Blomberg, L. G., Potemra, T. A., Murphree, J. S., Rich, F. J., and Stasiewicz, K. (1987) ‘A new method to derive “instantaneous” high-latitude potential distributions from satellite measurements including auroral imager data’, Geophys. Res. Lett., 14, 439–442.ADSCrossRefGoogle Scholar
- Newell, P.T. and Meng, C-I. (1989) ‘On quantifying the distinction between the low altitude cusp and the cleft/LLBL’, this volume.Google Scholar
- Papitashvili, V. O, Zaytzev, A. N., and Feldstein, Y. I. (1983) ‘Magnetic disturbances generated by the interplanetary magnetic field in the southern polar cap during summer’, Geomagn. Aeron., 23, 506–509.Google Scholar