[en] While the level of auroral zone geomagnetic activity, as measured by the AE index, is determined by the value of the southward component, B_s, of the interplanetary magnetic field (IMF), the delay in the geomagnetic response is modified by the microscale fluctuations of the IMF vector B. For extreme values of B_s(B_s> 5 nT and B_s = 0) the geomagnetic disturbances associated with small values of σ_z last longer than those associated with large σ_z. Conversely, for other values of B_s, the magnetosphere responds to the quasi-stationary interplanetary conditions with a shorter delay than to the time dependent solar wind conditions. Autocorrelations of the solar wind (SW), parameters evaluated for various time lags are always stronger when the initial value of σ_z is small than when it is large. Analysis of the autocorrelations and of the geomagnetic responses corresponding to them suggests that, for positive but not extremely large values of B_s, the temporal fluctuations of B trigger the internal magnetospheric (or the SW-magnetospheric coupling) processes which increase the observed time lags in the auroral zone geomagnetic activity. The value of σ_z is the SW parameter indicating whether the magnetosphere responds to SW conditions almost immediately (within less than ∼ 1 hour) or whether the magnetospheric response is more gradual and is delayed for another ∼ 1 to ∼ 4 hours. The data analyzed in this study indicate the existence of magnetospheric processes delaying the geomagnetic response to the SW conditions for B_s = 0 but they do not allow us to draw conclusions on the effects of σ_z when B_s is extremely high or equal to zero