Plasma Analysis of a Small-Bore, Arc-Armature Railgun
Final rept. May 1988-Dec 1989,
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Diagnostic measurements of plasma-armature properties have been made on a 9.3-mm square-bore, arc-driven railgun. The measurements include the total current carried by the arc, the voltages across the breech and muzzle ends of the gun tube, light output from the arc seen at points along the gun tube, and finally the time rate of change of the induction field associated with the armature current. From these data it is possible to infer the length of the arc and the current-density distribution within it as a function of time. The aggregate of this information is then used to provide input for a second mathematical model which allows deduction of the armature temperature, ionization state, pressure, and mass. Results of the data analysis are compared with those of one-dimensional steady-state theory and with conclusions from a recent 50-mm square-bore railgun experiment. The dissimilarities between the two experimentally derived results are noted, and possible reasons for those differences discussed.
- Electricity and Magnetism