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The fate of electrical charges in evaporating cloud droplets
Author(s) -
Thomson B. A.,
Iribarne J. V.
Publication year - 1978
Publication title -
reviews of geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.087
H-Index - 156
eISSN - 1944-9208
pISSN - 8755-1209
DOI - 10.1029/rg016i003p00431
Subject(s) - evaporation , ion , rayleigh scattering , atmosphere (unit) , materials science , chemical physics , instability , rayleigh–taylor instability , cloud physics , electric field , cloud computing , environmental science , mechanics , physics , meteorology , optics , quantum mechanics , computer science , operating system
Processes which have been previously considered as contributing to the loss of charge from cloud droplets in the atmosphere when the droplets evaporate are reviewed, and to the list is added the process of ion evaporation, which has been recently investigated in our laboratory. The relative efficiencies of the processes of Rayleigh instability, capture of ions of the opposite sign, field‐enhanced ion capture, and ion evaporation are compared. The cloud droplet charges and the amount of nonvolatile material in each droplet are critical in the comparison, and values of these in the atmosphere are briefly reviewed. It is concluded that in most situations, cloud droplets should evaporate and leave their charges on the solid residues which remain. Only when the droplets have been highly charged by processes in thunderclouds and when they are pure enough to evaporate to small sizes is it expected that Rayleigh instability or ion evaporation will become operative. We conclude that the process of field‐enhanced ion collection proposed by Dawson is ineffective in discharging cloud droplets.