Effect of Magnetic Anomalies on Very Low Frequency Discrete Emissions

Abstract

The author has suggested (Dowden 1962) that. the spectrogram (frequency v. time) shapes of V.L.F. discrete emissions can be explained as Doppler-shifted cyclotron radiation from electrons spiralling along a geomagnetic field line away from the observer. The emission frequency is given by Eidman (1958), It is reasonable to assume that y and ,8 are constant, that the electron density in the exosphere is everywhere proportional to the magnetic field, that 8 is either constant or a function of h only, and that ifo is given by the invariance of magnetic moment: sin 2 ifo/sin 2 ifoo = hlho, where subscript zero can refer to any known point such as the equatorial plane or point of minimum magnetic field. In this case the variation of frequency emitted by an electron spiralling along a field line is produced entirely by the variation of * Manuscript