Problems of the Motions of Solar Prominences

Abstract

YEARS of great solar activity, like those of A 1937-38, stand out as landmarks in the advance of our knowledge concerning the phenomena of the solar chromosphere. The quantitative study of prominence motions is little more than twenty years old and derives the greater part of its observational material from the peak years (1926-27 and 1937-38) of the last two solar cycles. Indeed, the recent studies by Max Waldmeier1 with the spectrohelioscope suggest that at times of maximum activity great eruptive prominences occur on the average about once a day somewhere,in the solar chromosphere. They may form the normal, though dramatic, end-phase in the life of every quiescent prominence.