Abstract

Lightning discharges, both intracloud and cloud-to-ground, lead to changes in electric field below the cloud that can be recorded with the use of a device known as an electric field mill. Electric field mills operate by rotating a grounded shield over an electrode to charge and discharge the electrode—which it then measures. Measurements of this charge oscillation can be then calibrated by applying known electric fields to the device and fitting a curve to the calibration data. This process was used to calibrate a field mill so as to analyze data from a thunderstorm that was approximately 16.8 miles away from the mill on June 15^th, 2018 and showed that the replenishing current of the storm was 3.5 amps.