Models and Radiation of Railgun Plasma Armatures with Non-Ideal Plasma Properties.
Final rept. 1 Oct 83-30 Sep 85,
WESTINGHOUSE RESEARCH AND DEVELOPMENT CENTER PITTSBURGH PA
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A theoretical framework for modeling the characteristics of railgun plasma armatures is developed taking into account non ideal transport properties and equation of state. The electrical resistivity of the plasma is calculated as a sum of contributions from electron ion and electron neutral collisions. Non ideal correction to the ionization potential and pressure in Sahas equation and th e equation of state is included. A steady-state magneto-gasdynamic model improved over earlier works is developed. In this model, the net Lorentz force exerted on the plasma armature is exactly accounted for. The model studies the radiation emanating from the plasma armature. It is found, on the one hand, that the radiation from the plasma armature under the conditions of most railgun experiments conducted in the past is sufficiently high to cause ablation. On the other hand, the modelling results also indicate that there indeed exist domains of operating parameters in which radiative ablation of the wall materials can be completely eliminated. Whether these favorable domains of operating parameters can be realized in practice remains a development of the future, though preliminary experiments conducted in a companion program sponsored by DoE and experiments in other institutions based upon the theoretical recommendations developed here have produced significant reduction of ablation of the rails. It should be emphasized, however, that ablation mechanisms other than radiation could also be present.
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