Satellite observations of signals from a Soviet mid-latitude VLF transmitter in the magnetic-conjugate region

The results of the Intercosmos-19 satellite experiment which receives VLF signals arriving via a magnetospheric path have been examined. The reception zone in the magnetically conjugate region (MCR) has been shown to be centred near the L-value (2.6) of the transmitter of 15 kHZ radio waves. The received signals arrive at the MCR with wave normal angles to the geomagnetic field, ψ, far from the resonance cone. These results indicate an effective amplification of the signal in the magnetosphere by 10–15 dB and effective ducting of VLF waves across the equatorial plane of the magnetosphere.