Kathode Rays and the Aurora

Abstract

THE idea that kathode rays play a part in aurora has been advanced by several physicists. Prof. Kr. Birkeland (“Expedition Norvegienne,” 1899–1900, Christiania, 1901) has described a number of phenomena produced by kathode rays in the neighbourhood of a magnetised sphere, which resemble various types of aurora. He supposed the sun to be a primary source for kathode rays, which might set up secondary rays in the earth's atmosphere. Mr. C. Stφrmer has carried out elaborate calculations as to the possible ways in which electrified particles coming from a great distance can approach a magnetised “earth”; his results tend to limit the approaching particles to the space near the magnetic poles. Prof. S. Arrhenius has supposed electrified particles to be driven from the sun by the repulsion of light and to reach the earth's atmosphere in about two days, originating aurora and magnetic storms.