Storm-time variation of the horizontal and vertical components of the geomagnetic fields and rate of induction at different latitudes

Geomagnetic field H, Z, and electromagnetic induction features of coronal mass ejections in association with geomagnetic storm at African longitudes

“…On 22 June, the solar wind signature with dH/dt was observed between 5:00 h and 6:00 h, another peak was noticed around 18:00 h and 19:00 h produced by shock in the solar wind. Nighttime enhancement of time derivatives of the horizontal geomagnetic field was observed at MBO, HBK, HER and TAM with values of 60.37 nT/min, 24 nT/min, 18 nT/min and 58 nT/min at19:00 h respectively. The time derivatives of the horizontal geomagnetic field exhibit the same pattern of variation during the geomagnetic storm(Figure 2 (a-e)).…”

“…The equatorial daytime enhancement of geomagnetic field time derivatives is linked to the influence of Cowling conductivity effects. The alteration in the intensity and distribution of the ring currents, auroral electrojets, and field-aligned currents can affect the time derivatives of the geomagnetic fields at HBK, HER and TAM[19] (seeFigure 1(a-f)).Figure 2 (a-e) depicts time derivatives of the horizontal geomagnetic field variation on 22 June 2015. Nighttime enhancement was noticed around 19:00 h through 24:00 h, this implies that there is a visible nighttime enhancement of geomagnetic disturbance variation in dH/dt.…”