A New-Type Source of Power Line Harmonic Radiation Possibly Located on the Kola Peninsula

A new-type source of power line harmonic radiation (PLHR) is described in this paper to point out its significance to the magnetospheric emissions. Characteristic electromagnetic fields were observed over the Kola Peninsula, northern Russia, during the flight of the balloon B15-2N in 1982. The source is characterized by (a) the fundamental frequency of 24.4 Hz, (b) the harmonic spectrum continuously extending up to VLF, and (c) the isolation from commercial power lines. These characteristics are different from the previously reported PLHR sources that could trigger the magnetospheric emissions. Based on the low impedance field and the amplitude variation along the balloon trajectory, the source can be modeled by a horizontal electric dipole or a horizontal magnetic dipole, and then the source distance is estimated within the induction area of a few hundred kilometers. The most probable source is an electric railroad or a single-phase power line, driven by an isolated power generator, and located on the Kola Peninsula. Estimating the radiation power through the ionosphere, it is shown that enough power to trigger magnetospheric emissions may be radiated into the magnetosphere from the source. Therefore, it is suggested that the source can be recognized as a new-type PLHR source possibly related to magnetospheric emissions.