Radius Ratios of Argon Pinches

Abstract

According to a new theory based on energy balance, the radius ratio Yp/Yo of a constant-current plasma pinch depends only on the value of the effective specific heat ratio y of the pinched plasma. In this paper the value of y for argon is computed as a function of temperature. From these values the constant-current pinch ratios are computed. The results show argon pinch ratios of about o· 08 from (2-4) x 106 K, rising to 0·18 at 1·1 x 107 K and to O· 27 at 108 K. There is good agreement between this theory and an Imperial College measurement of Y o/ro ~ 0 ·17 for a constant-current argon pinch at an estimated temperature of 1 keY.