Hydromagnetic emissions associated with the magnetic storm of September 30, 1961

Abstract

The magnetic storm of September 30 through October 1,1961, was the first severe magnetic disturbance from which data were obtained simultaneously from satellite, balloon, and ground observations [Bryant et al., 1962; Hoffman et al., 1962; Winckler et al., 1962; also ‘September Event,’ special session of the First Western National Meeting, American Geophysical Union, December 27–29, 1961, Los Angeles, California]. In view of the geophysical importance of this event it seems worth while to present the frequency-time characteristics of micropulsations (both hm emissions and noise bursts) throughout the disturbed period. Sonagrams of a 24-hour period including the storm are presented in Figures 1 and 2. The sonagrams were obtained from a magnetic tape recording of the signals detected by an induction magnetometer at Palo Alto, California. The instrumentation is described elsewhere [Tepley, 1961a]. The sonagrams include a 1-minute short-out period at the beginning of each hour, followed by a 1-minute calibration at cps.