A highly sensitive field mill for registering weak and strong variations of the electric-field intensity of the Earth’s atmosphere

Abstract

The design and the principle of operation of an electric-field intensity meter (field mill) are described. The instrument is intended for determining the energy, time, and spatial parameters of the atmospheric electric field near the Earth’s surface when monitoring a geophysical situation. The developed field mill allows registering both weak variations of the electric-field intensity in the atmosphere, such as global electromagnetic Schumann resonances, and strong variations that are caused by the passage of atmospheric fronts, heavy clouds, thunderstorms, etc. The instrument has a threshold sensitivity of ~10^–3 V/(m Hz^1/2) within a frequency range of 10^–3–25 Hz and a wide dynamic range of 120 dB.