Study of individual geomagnetic storms in terms of the solar wind

This paper summarizes a study of the development of a large number of geomagnetic storms in terms of the solar wind-magnetosphere energy coupling function epsilon, the AE and Dst indices. It is shown that the maximum magnitude of the main phase decrease (Dst) is determined primarily by the peak value of epsilon; for epsilon<1019 ergs-1, approximately 1019 ergs-1, 1019-1020 ergs-1, >approximately 1020 ergs-1, the maximum values of Dst are <50γ, approximately 50γ, approximately 100γ and >approximately 200γ, respectively. A few examples for different peak values of epsilon (and thus of Dst) are presented and examined in detail. Substorm activity during storms is well controlled by epsilon. (author)