Generation of high-velocity plasma flows in railgun channels filled with gases of various density

We have studied the motion of a plasma piston (PP) in the channel of an electromagnetic railgun accelerator with a cross-sectional area of 36 and 86 mm$^2$. The accelerator was placed in a chamber that could be evacuated and then filled with helium or argon at a pressure within 25–250 Torr. It is established that the stationary PP velocity in the channel depends on the gas type and pressure. The results are satisfactorily described by the proposed model. Experimental data can be used for evaluating the effective running inductance of the accelerator and the coefficient of erosion of the electrode material.