Experimental study of cloud formation by intense electric fields

Cloud and fog formation under an electric field has been studied experiment ally using a Wilson's cloud chamber with a supercooled atmosphere of ethano l. The threshold electric field to generate dense clouds using parallel pla te electrodes was about 4 kV/m as estimated from the generated cloud positi on and from a model experiment of an electric field simulation using a wate r bath. Positive ions produced by the ionization of the atmosphere condense nuclei for the generation of fogs and clouds. Old legends and retrospectiv e reports on earthquake fogs (EQFs) and clouds (EQCs) prior to a major shoc k may be elucidated by the condensation of vapor under an intense electric field, similar to earthquake lightning (EQL) due to electro-atmospheric are and dark discharges. A plume cloud like a streamer discharge was produced from a needle electrode, which exhibited similarities to tornado-type cloud s photographed before the Kobe earthquake. Electric discharges of clouds by a wired rocket or laser-induced lightning are suggested to terminate the e lectric energy for the upward vortex flow of a tornado.