Effect of the total solar eclipse of 20 March 2015 on the ELF propagation over high‐latitude paths

Abstract

Propagation of the artificial electromagnetic waves with frequency of 82 Hz in the Earth‐ionosphere waveguide was observed during the solar eclipse on both partially and totally obscured high‐latitude paths with a length of 450–1200 km. Field excitation was monitored by the reference measurements in the near zone of the transmitter, which are free of the ionospheric influence. It is found that the amplitude of the field at the remote points varied depending on the solar illumination and solar elevation angle. We suppose that this effect was probably caused by the increase in the effective height of the ionospheric D layer, just as it was previously observed in VLF. The obtained results demonstrate the response of the propagating extremely low frequency (ELF, 3–300 Hz) wave to the change in the ionospheric boundary. This effect has been for the first time observed in this frequency range during a total solar eclipse.

Effects of the Great American Solar Eclipse on the lower ionosphere observed with VLF waves

“…During a solar eclipse, the UV solar flux decreases and consequently, the rate of ionization in the D-region is strongly reduced, causing an elevation of the effective height of the reflecting ionospheric layer. Thus the conditions in the lower ionosphere approach to those observed during the nighttime (Mendes Da Costa et al, 1995;Tereshchenko et al, 2015). Making solar eclipses very helpful natural setups to study the ionization dynamics of the lower ionosphere.…”