MLR events and associated triggered emissions observed by DEMETER Original Research Article

This paper gives an overview of different sets of new Magnetospheric Line Radiation (MLR) observed by the satellite DEMETER. Different types of emissions have been observed: emissions called Power Line Harmonic Radiation (PLHR) with frequency lines exactly separated by 50/100 or 60/120 Hz, emissions with frequency lines not exactly separated by 50/100 or 60/120 Hz and drifting in frequency (MLR). By comparison with past observations one can say that some MLR events are due to man-made PLHR which may suffer a non-linear gyro-resonant interaction at the magnetic equator. It is also shown that periodic emissions are very often associated with the MLR. In this case the origin of these waves is natural. The lines are produced by the periodicity and the frequency band limits of the individual elements which causes the appearance of lines on the spectrograms. Finally the paper shows that MLR can trigger emissions.