Measurements of plasma properties from a large bore, plasma armature railgun

Measurements from four firings of the large-bore railgun CHECMATE have been used to infer fundamental properties of the plasma which comprises the arc armature. A set of diagnostic measurements was devised in an attempt to quantify the armature length, current density, and conductivity. The quantities measured were muzzle voltage, breech voltage, armature induction field and inbore light emission. The authors describe diagnostic probes, the data accumulated in each of the firings, and an unfolding analysis utilized to derive armature properties from the data. The information is largely derived by the detection of the armature's induction field.>