Features of Radio Signal Propagation in the VLF Range at High Latitudes during Solar Proton Events

Abstract

In this paper, we study the amplitude and phase characteristics of VLF signals of an anthropogenicorigin during solar proton events using the methods of a computational experiment. We consider the events ofOctober 30, 2003 and January 23, 2012. Electron density profiles are plotted using data from the VHF EISCATincoherent scatter radar located in Tromsø, Norway. Based on the processed data of computational experiments,that under the conditions of solar proton events, mainly amplitude distortions of VLF signals wereshown to be observed while there is a frequency dependence of the magnitude of distortions of the signals ofthe RSDN-20 long-range navigation radio system. The signal phases of the RSDN-20 system are less affectedby weak solar proton events. The effect of the lower boundary of the Earth-ionosphere waveguide in the casesof propagation of signals from the RSDN-20 system over the surface of land and ocean during a solar protonevent was studied.