Calculation of the Fields in a Closed Cylinder Resulting from an Electromagnetic Pulse

A technique is discussed which simplifies the calculation of fields inside a closed circular cylinder resulting from an electromagnetic pulse. The pulse shape is a double exponential function, with unity amplitude. Three pulses are considered which have .2, 2, and 20 microsecond rise times, and decay times approximately 10 times longer than the rise times. The cylinder is assumed to be 7.5 meters long, 12 cm in diameter, and made of aluminum 1/4 cm thick. The dimensions of the cavity are sufficiently small so that internal resonances are not excited by the highest significant frequency of the shortest pulse.