Surface determination of the air-earth electrical current density using co-located sensors of different geometry

Bennett, A. J. and Harrison, R. G. ORCID: https://orcid.org/0000-0003-0693-347X (2006) Surface determination of the air-earth electrical current density using co-located sensors of different geometry. Review Of Scientific Instruments, 77 (6). 016104.

Abstract/Summary

A vertical conduction current flows in the atmosphere as a result of the global atmospheric electric circuit. The current at the surface consists of the conduction current and a locally generated displacement current, which are often approximately equal in magnitude. A method of separating the two currents using two collectors of different geometry is investigated. The picoammeters connected to the collectors have a RC time constant of approximately 3 s, permitting the investigation of higher frequency air-earth current changes than previously achieved. The displacement current component of the air-earth current derived from the instrument agrees with calculations using simultaneous data from a co-located fast response electric field mill. The mean value of the nondisplacement current measured over 9 h was 1.76 +/- 0.002 pA m(-2). (c) 2006 American Institute of Physics.