Detection of Whistler Waves

A whistler wave is a very low frequency electromagnetic wave generated by lightning discharges. As the electromagnetic wave travels through the plasma environments of the ionosphere and magnetosphere, it undergoes dispersion of a several thousand kilohertz. Because the propagation velocity decreases with frequency, the lower frequency components of the wave arrive later than the higher frequency components. Thus, a radio station picking up a whistler wave would detect a signal that has decreasing frequency in time. Since the frequency range of the whistler waves lies within the human audible range, it would be perceived as a descending tone if converted into audio, hence its name. A whistler wave bounces back and forth across opposite sides of the planet, and the particular hop number and direction is indicated by a number and a sign. A 0+ whistler indicates a wave on its first upward path, whereas a 1whistler indicates a wave on its downward path after its first reflection. In this project, we are interested in the automatic detection of the presence of 0+ whistler waves from radio data collected by the DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite.