Study of a railgun plasma armature

An experimental and theoretical study of a railgun plasma is presented. The experimental results have been obtained by recording the voltage and current variations as well as the spectral emission of the plasma. The gas pressure, helium, or air in contact with the exploding foil has been varied from 0.1 to 2 MPa. The apparatus consisted of a test chamber simulating a railgun facility. To complete the study, some measurements of the plasma characteristics in the 500-kJ EMA 1 railgun system have been recorded. It is shown that the resistance of the plasma, which is 15 m Omega at 10 kA, decreases to 0.2 m Omega at 500 kA. These results indicate the effect of the energy flow to the walls and that of the ionization potential of the gas in contact with the exploding foil at lower currents. >