Experimental indication of a buffer zone between the plasma armature of an EML and the projectile [EM launchers]

The time-resolved light emission observed at 4000 Å with a phototube at a fixed location along the bore indicates that a warm, weakly ionized region may exist between the rear of the projectile and the armature. This observation supports the fact that the rear of the projectile shows very little ablation. An attempt is made to observe this buffer region using a combined fiber-optic probe and a conductivity probe located at the same bore position. The speed of the armature is obtained from interconnected B-probes and the theory and use of this diagnostic is discussed