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Electric field growth in thunderclouds
Author(s) -
Winn William P.,
Byerley L. G.
Publication year - 1975
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49710143017
Subject(s) - electric field , lightning (connector) , atmospheric electricity , physics , spheres , electric charge , field (mathematics) , computational physics , meteorology , astronomy , power (physics) , mathematics , quantum mechanics , pure mathematics
We have constructed a balloon‐borne instrument for measuring the magnitude of the horizontal component of the electric field in thunderclouds. It consists of two hollow, copper spheres 15cm in diameter held 2cm apart. The spheres spin about an axis that can be described as the perpendicular bisector of the line segment between the centres of the spheres. The sinusoidally‐varying charge that is induced on the spheres by an electric field is amplified and telemetered to ground. The amplifier and telemetry transmitters are located inside one of the spheres. The spheres also serve as the telemetry antenna. The time behaviour of the electric field in the cloud is substantially different than that at the ground. The effects of corona discharge from the ground and of the finite conductivity of the air outside the cloud seem to be negligible in the presence of the intense field near a region of charge inside a cloud. Measurements of electric field intensities inside a cloud just before and after a lightning flash when combined with measurements at the ground can be used to obtain an approximate value for the total quantity of charge in a region of cloud just before it is partially discharged by lightning. In two cases the charge just before lightning was estimated to be −120C and −160C. During a brief interval in one of our flights the electric field at the balloon reflected the time behaviour of the electric field in the cloud; the electric field increased linearly with time between lightning flashes.