Proceedings of the Physical Society of London · 1924 · 339 citations · 0 references
EngineeringPhysicsElectrostatic DischargeGlow DischargeCloud DynamicElectric FieldsMagnetohydrodynamicsCorpuscular RadiationCosmic RayElectric FieldCloud PhysicsElectric Generator
Thunderclouds generate electric fields by separating charges, producing currents of several amperes and potential differences up to a million kilovolts. The paper draws attention to three effects of thundercloud electric fields that can occur even in the absence of thunder. The electric field can ionize air at high altitudes, produce discharge from pointed earthed conductors contributing to ground–cloud current and ground ionization, and accelerate particles to generate highly penetrating corpuscular radiation.
A thundercloud is an electric generator in which the separation of positive and negative charges occurs at a rate corresponding to a current which may amount to some amperes; the potential difference between its poles may reach values of the order of a million kilovolts. Attention is drawn to three effects of the electric field of thunderclouds or shower clouds (all of which may occur even when there is no thunder). (1) The electric field of the cloud may cause ionization at great heights, the result being continuous or discontinuous discharge between the cloud and the upper atmosphere. (2) Discharge from pointed earthed conductors is likely to constitute an important part of the current between the ground and the base of a thundercloud, and the resulting ionization near the ground may be large. (3) By its accelerating action on particles the electric field of a thundercloud may produce extremely penetrating corpuscular radiation.