Electromagnetic simulation of missile exhaust plumes, construction and testing of a physical simulator and the predicted results of a theoretical thin wire rocket/plume model

A full scale simulator of a typical low attitude missile plume was constructed. Carbon loaded foam was used in the model to simulate the electrical conductivity of the ionized exhaust gases expelled from the solid propellant motor. Theoretical computations made with the Low Altitude Plume Program (LAPP) were used to determine the distribution of conductivity in the simulator. A full size missile with the plume simulator attached was tested in an anechoic chamber. The missile was exposed to electromagnetic radiation and the voltage at an internal test point in the circuitry was measured to determine the amount of energy that was coupled through the apertures in the missile. Azimuthal interference patterns were constructed by varying the angle of the incident radiation. The experimental patterns are in fair agreement with those computed from a simple theoretical electromagnetic analysis.