Charge Distribution in a Cloud Assessed from the Energetic Particle Flux Measured under the Cloud

Abstract

An increase in the flux of energetic particles under thunderstorm clouds is a result of the multiplication and acceleration of particles of secondary cosmic rays in the electric field of the cloud. Study of the particle multiplication mechanisms requires an assessment of the electrical properties of clouds. In this paper, we propose a method for evaluating the electrical structure of a cloud that creates a flux of energetic particles. The developed technique for estimating the distribution of a charge in the cloud is based on the ground-based measurements of the electric field and energetic particle flux. The technique was used to study the clouds that create the descending fluxes of energetic particles observed at the Aragats Research Station. The characteristic charge distribution involves a two-layer structure with a charge density of 0.5–5 nC/m³ in the lower layer and –0.2…–3 nC/m³ in the upper layer. The total charges of the two charge regions are in the range of 1– 20 and –1…–30 C, respectively.