The development of a transient magnetic field measurement technique for implementation on a fuselage-like test setup

Summary form only given, as follows. The susceptibility of airborne vehicles to electromagnetic transients has been studied for many years, however the application of new structural and electrical technology advances has caused a re-examination of the threats due to both natural phenomena and man made environments. In the case of lightning attachment, the current flows along the surface of the conducting fuselage and disperses around the circumference. A portion of it also penetrates through the conductive skin (by diffusion) resulting in transient electromagnetic fields on the inside that can result in electromagnetic interference to onboard electronics. In the case of a pulsed power system driving a dedicated weapon or countermeasure device, the "return" current phenomena can be very similar to the natural lightning, particularly if system components are distributed throughout the vehicle. In the laboratory, an aluminum test cylinder, representative in size and construction of a fighter-type aircraft fuselage, was subjected to high current pulses.. A two-stage Marx-type circuit was customized to drive the coaxial load consisting of the cylinder and return leads. The initial phase of the investigation was the modeling of the entire experimental circuit in order to calculate the total surface current and compare it to the measured values. During the second phase, a new technique is being developed to determine the magnitude of magnetic flux density outside and inside the cylinder as a result of transient currents flowing on along the cylinder. To this end, new two-dimensional B-field probes have been designed and fabricated. The mating of these probes with a wide bandwidth fiberoptic system for transient data acquisition and the overall system calibration procedures will be presented.