Theoretical analysis on the penetration of power line harmonic radiation into the ionosphere

Abstract

Radiation at the fundamental and higher harmonic frequencies from power lines affects the environment of Earth's ionosphere and magnetosphere, because such radiation may lead to the enhanced electron precipitation into the ionosphere due to wave‐particle interactions in the magnetosphere. In this paper we analyze theoretically the penetration of power line radiation, taking into account the presence of the anisotropic, homogeneous ionosphere. The electromagnetic field can be formulated by using the Fourier transform and field distribution obtained by proper deformation of the integral path with consideration of singularities. We calculate the field distribution as a function of altitude and distance from the source. From the numerical results, we can find several new findings: (1) the effect of the radiation from power line is limited in a relatively narrow region below the cutoff frequency of the guided mode in the Earth‐ionosphere waveguide, while the region affected by the power line radiation becomes much wider if the guided modes exist, (2) the radiated fields are directed almost horizontally, and (3) the altitude distribution of electromagnetic fields changes at the ion gyrofrequency. Comparison with the observed data shows a good agreement with respect to the region affected by power line radiation.

Power line harmonic radiation observed by satellite: Properties and propagation through the ionosphere

“…Consequently, the observed time durations correspond more likely to the spatial dimensions of individual PLHR events. The average corresponding spatial dimension of 156 km (median 90 km) is in a relatively good agreement with theoretically calculated dimensions of the affected region [Ando et al, 2002].…”

“…Moreover, they have shown that the peak intensity of PLHR is larger during the night than during the day, suggesting different penetration characteristics of the ionosphere as a possible explanation. Ando et al [2002] performed a theoretical analysis of penetration of PLHR into the ionosphere and estimated the horizontal size of the region where the electromagnetic field is strong to about ±200 km from the source, not extending with higher altitude.…”

ELF magnetospheric lines observed by DEMETER

“…Simulations have also been performed by Nunn et al (1999) to explain ground observations of PLHR and associated triggered emissions in Finland. Recently, Ando et al (2002) analyzed the penetration of PLHR in the presence of an ionosphere with a single ion and underlined the importance of the ion gyrofrequency relative to the wave frequency of this man-made emission.…”

Simultaneous observation on board a satellite and on the ground of large‐scale magnetospheric line radiation

“…Simulations have also been performed by Nunn et al [1999] to explain ground observations of PLHR and associated triggered emissions in Finland. Recently, Ando et al [2002] analyzed the penetration of PLHR through the ionosphere and underlined the importance of the ion gyrofrequency relatively to the wave frequency of this man-made emission. This paper is related to a MLR event simultaneously observed by the satellite DEMETER and a ground-based experiment during a special campaign.…”