A note on whistlers observed above the ionosphere

Abstract

The sensing coil of the proton precession magnetometer carried on the Vanguard III satellite also served as an antenna for detecting audio-frequency electromagnetic waves. A preliminary analysis is given for about one hundred whistlers observed September 18 through December 12, 1959, at low latitudes over the altitude range 510 to 3750 km. About 90 per cent of the whistler occurrences are between 6 PM and 6 AM local time indicating a low nighttime absorption by the ionosphere. The intensity of the H component of the wave is estimated to be between 0.01 and 0.5 gamma, with that of a few signals exceeding 1 gamma.