Response of a Magnetospheric Storm in the Atmospheric Electric Field of the Midlatitudes

The response of strong magnetic storms in variations of the electric field of the near-ground atmosphere of the midlatitudes are studied according to data from long-term observations of aeroelectric (Ez) and geomagnetic fields at the midlatitude Borok Geophysical Observatory. For the period 1998–2015, 19 strong and very strong magnetic storms with a minimal Dst index of < –100 nT and a maximal index value of Kp > 7, which correspond to undisturbed meteorological conditions of the lower atmosphere (i.e., good weather conditions), are identified at Borok Observatory. The effect of a magnetic storm on changes in the electric field of the near-surface atmosphere is shown to be more efficiently manifested in the daytime around noon. A statistically significant variation in the strength of the aeroelectric field was found. It was characterized by an increase in the Ez value over a time interval of ±4 h relative to the time of the minimum of the Dst variation of the magnetic storm.