Demagnetization Scheme for Avoiding Magnetic Mines Under the Exposure of Earth Magnetic Field

摘要

Demagnetization of warship is needed to reduce residual magnetization to avoid the detection of magnetic mines. However, after a warship was demagnetized, it may be magnetized again by the earth magnetic field during the operation. Conventional deperming protocol does not consider to magnetize again by earth magnetic field after demagnetization. To develop a robust deperming protocol to the influence of earth magnetic field, this paper proposes a protocol that demagnetization finished in a region where the interaction field is large on the Priesach plane. It was found to be more effective by analyzing the trace on the Preisach model and it is proved by experiment. Therefore, it is expected to prevent to magnetize again by earth magnetic field when applying proposed protocol.