Some Results and Limitations of Prony Analysis of In-Flight Lightning Data,
Abstract:
Recent results have shown that the electromagnetic resonances of an aircraft can be excited by lightning. Each resonance may be characterized by a particular frequency and damping rate, and these two quantities taken together constitute a natural frequency. One way to determine the natural frequencies is by applying Prony analysis to waveforms measured during lightning strikes. This involves a numerical technique for fitting a series of damped sinusoids to the measured waveforms. Electric and magnetic field waveforms recorded on the N.A.S.A F-106B aircraft during lightning strikes have been analyzed using the Prony technique. A number of natural frequencies have been determined, and these are in substantial agreement with the frequencies observed on a laboratory model of the airplane. The process of determining the frequencies is not without difficulties, and some waveforms yield much better results than others. Author