Cosmic Thunderstorms.--In a recent article in this JOURNAL, 1 and in other contributions, 2 the writer showed that his electrical discharge theory of those magnetic storms, which follow outbursts at the sun's surface by periods of the order of a day, led to the surprising conclusion that temperatures of the order of 400,000,000ยฐK must be reached in these discharges somewhere between the sun and the earth.
In another presentation 3 of this work the writer emphasized, however, that this theoretical conclusion need not surprise us too much, since temperatures of over one million degrees are observed in the solar corona. Temperatures of this order too have been obtained in electrical discharges in the laboratory. Furthermore, the point was made that other conditions exist in which a considerable increase in temperature occurs when these discharges are propagated down a density gradient in stellar atmospheres. I11 the combination-spectra stars, for example, in which the density gradient is very much less than it is in the solar atmosphere, the discharge temperature similarly increases from about 5000ยฐK or 10,000ยฐK, at the start of the outburst, to a final value of over a million degrees absolute. In the article itself 1 it was pointed out that these long atmospheric electrical discharges act as "energy pumps," liberating in regions of low gas density the electric field energy which had been generated lower down in the stars' atmospheres.
Nevertheless this deduction from the theory, while put forward with some confidence in view of the theory's mounting success in accounting for other gas movements in stellar and galactic atmospheres, was also recognized as a possible source of criticism.
It was therefore reassuring when the writer's attention was drawn to a reference 4 to the work of the U. S. Naval Scientists. In their study of the phenomena accompanying solar flares, which, it was suggested earlier 5 are electrical discharges, these Scientists have found evidence outside the earth's atmosphere of X-rays having energies of 80,000 eV, and therefore evidence of the existence of temperatures of 100,000,000ยฐK, in good agreement with the theoretical predictions.