Fig. 11
From: Two current systems in the preliminary phase of sudden commencements in the magnetosphere
Temporal spread of the magnetospheric SC signal front, indicated as the edge of the positive region of \(|\frac{\mathrm{d}v}{\mathrm{d}t}|\). The black and blue arrows in the panels of t = 4.0 min to t = 6.2 min indicate the SC front in the magnetosphere and the magnetosheath, respectively. It is evident that the SC front arrives at the night-side magnetosphere at 6.2 min, when the PI current system in the ionosphere does not reach the nightside. The line contours show the pressure in the equatorial plane. Irregular patterns of \(|\frac{\mathrm{d}v}{\mathrm{d}t}|\) in the night-side magnetosphere are fluctuations. We do not discuss the fluctuations in this paper because they do not play any roles in the propagation of the SC signal