Prediction and Analysis of Transient Eddy - Current Probe Signals

In eddy-current nondestructive evaluation, the electromagnetic field is usually excited by a probe carrying a time-harmonic current and flaw information inferred from the amplitude and phase of the probe signal. In principle, transient excitation of eddy-currents would seem to offer great advantages since the probe response contains the equivalent information of a spectrum of frequencies. This paper explores a number of basic transient solutions due to normal air-cored coils and shows how the induced emf in a coil is related to its coupling coefficient.