Supersonic flow in ablative discharge capillaries

The Mach number equation for plasma flow in ablative discharge capillaries was derived from a set of 1-D flow equations which incorporate the ablation and Ohmic dissipation processes. By examining this equation it is concluded that, while in the case of a capillary with a constant cross section the flow is subsonic and the sound velocity can be reached only at the open end, there is a possibility to reach supersonic plasma velocities inside a capillary with a monotonically increasing cross-sectional area. (C) 1997 Elsevier Science B.V.