Worldwide Simultaneity of Occurrence of a Q-type ELF Burst in the Schumann Resonance Frequency Range

Abstract

For the past ten years a number of workers have investigated naturally occuring ELF electromagnetic noises from different points of interest. Many recorded examples of noise waveforms have been exibited in their papers (Schumann and Konig, and Yasuhara (1966) have classified the vertical electric component of these ELF noises, which were observed using a "ball antenna", into three categories; ELF flashes, ELF bursts, and "ELF continuous". ELF flashes probably originate from a kind of lightning discharge whithin a distance of about 1,000km, and show a simple damped wavef orm. ELF bursts have two categories; N-and Q-types. N-type bursts have preceding VLF components and the source distances have been estimated to be in the range from 2,500km to 5,000km. The origin of N-type bursts may also be lightning discharges. Q-type bursts have no VLF components, and their amplitudes are rather larger than N-type bursts. The frequency of occurrence of Q-type bursts is found to be larger than that of N-type bursts, provided counting is restricted to bursts with amplitudes of over 400jV/m.