Propagation Spectrograms of Whistler-Mode Radiation from Lightning

Abstract—We show images of propagation spectrograms based on spacecraft observations of electromagnetic radiation of light-ning strokes. We use multicomponent data of the DEMETER spacecraft, and we match observations of fractional-hop whistler signals with the source lightning strokes in the Mediterranean region. We perform multidimensional analysis of the spacecraft data, and we obtain detailed information on wave polarization characteristics and propagation directions. Index Terms—DEMETER microsatellite, fractional-hop whistlers, ionospheric wave propagation, lightning induced whistlers, multicomponent wave measurements. L IGHTNING strokes are powerful phenomena, showingnot only the known luminous effects but also emitting radiation in other parts of the electromagnetic spectrum. For example, at frequencies of hundreds of hertz to a few kilohertz, electromagnetic radiation from lightning strokes can penetrat