Abstract
The transient response of a thin, rectangular conducting plate in a conductive host medium is presented for a horizontal-loop electromagnetic (EM) system considering both a step and pulse EM method (PEM) excitation. For a shallow plate-like conductor, the current-gathering effect is preceded by a blanking effect. However, for deeper plates, current gathering was not observed. The effect of increasing plate depth, the ratio of the time constant of the plate to that of the host, and the plate time constant on the temporal characteristics of blanking and current gathering are investigated. The onset time for current gathering is independent of the plate time constant and is essentially a property of the host medium. At later observations (> or =5 ms) the decay of the plate in the host resembles the decay of the plate in free air. An interpretation scheme is proposed to determine plate parameters for Crone PEM measurements using the responses in two relatively late time channels.
