Figure 3

Annual variation of geomagnetic responses to various solar wind inputs. Annual averages of (a) hourly Dst, (b) Kp, (c) hourly AL, and (d) probability of Kp ≥ 4 for several fixed values of modified Akasofu’s epsilon \(\epsilon ' = (4\pi /\mu _{0})\cdot \textit {V}_{\textit {SW}}\cdot \textit {B}_{\text {tan}}^{2}\cdot \textit {sin}^{4}(\theta _{c}/2\)), and (e) annual averages of hourly Dst for fixed several values of solar wind proton density N _P (hourly values) are plotted with different colors. The selected ε ^′ and N _P values are given in the legend. The solar F10.7 index is plotted below each panel. The reason for the singularity of the Dst values in 1965 is unknown, and that point is plotted in dashed lines.