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Electrification produced by the rupture of large water drops in an electric field
Author(s) -
Matthews J. H.,
Mason B. J.
Publication year - 1964
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.49709038506
Subject(s) - electric field , drop (telecommunication) , mechanics , toroid , physics , electric charge , sign (mathematics) , electrical engineering , nuclear physics , plasma , mathematics , mathematical analysis , quantum mechanics , engineering
The deformation and break‐up of large freely‐falling water drops, of diameter greater than 15 mm, has been studied by high‐speed photography. In confirmation of observations by earlier workers, the drops become distorted and flattened and, if their velocity relative to the air exceeds a critical value, they blow up to form a large bag supported on a toroidal ring of liquid. Eventually the bag bursts to produce a fine spray of droplets and the toroid breaks up into several large drops. the critical conditions for break up and the rate of expansion of the bag are studied experimentally and the observations are compared with available theory. When the drops break in a vertical electric field, a charge of one sign is induced on the bag and a charge of opposite sign appears on the toroidal ring. Disintegration of the drop causes a separation of charge. the charges carried by the large fragments of drops breaking in fields of 30 V/cm, 300 V/cm and 1,500 V/cm have been measured by an induction method. In a downwardly‐directed field of 300 V/cm, such as may be provided by the primary charging mechanism of a thunderstorm, the fragments carry charges of order 1 e.s.u./g., i.e., two orders of magnitude greater than those measured by Simpson in the absence of a field, and may therefore contribute significantly to the formation of the subsidiary positive charge that sometimes appears in the bases of thunderclouds.