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

Abstract : Very Low Frequency (VLF) spectrograms show sometimes sets of lines called MLR (Magnetospheric Line Radiation) with frequency spacing close to 50 or 60 Hz. It is very tempting to attribute these MLR to Power Line Harmonic Radiation (PLHR). PLHR are the ELF and VLF waves radiated by electric power systems at the harmonic frequencies of 50 or 60 Hz. Here we show for the first time large scale MLR observed simultaneously on ground and on board a low altitude satellite which is flying over the same zone. This two hours event is observed over a large area in the Northern hemisphere ($7,400,000 km 2) and in the conjugate region. It is hypothesized that these MLR are due to PLHR propagating in the ionosphere and the magnetosphere. When they cross the equator, the PLHR undergo a nonlinear interaction with particles and may play a role in the dynamics of the radiation belts.