VLF emissions and electron precipitations stimulated by emissions of powertransmission line harmonics

A variety of VLF emissions stimulated by the emission of power transmission line harmonics has been revealed in sonograms as a stable frequency-period ic structure. In contrast to ordinary line harmonics, these emissions are c haracterized by a considerable (more than 50%) spectrum widening and the ab sence of a decrease in their amplitude with increasing number of harmonics. It has been demonstrated that the periodic spectral structure is observed only during periods of moderate activity and pseudobreakups and is absent o n geophysically quiet and magnetically active days. The signs of the correl ation between these emissions and the aurora have been identified.