Application of energy balance to compute plasma pinch ratios

From energy balance the pinch ratio r/sub p//r0 (where r/sub p/ = equilibrium pinch radius and r0 = original radius) may be directly computed for the case of a constant current electromagnetic pinch. For the case of a varying current, to solve the energy integral requires the current as a function of the pinch radius. To achieve this an approximate pinch trajectory is first estimated using a snow-plow model. This trajectory by itself gives a zero pinch ratio but it enables the energy integral to be performed. The theoretically predicted values of r/sub p//r0 for several cases are found to be in satisfactory agreement with experimental values. This procedure would be useful for designers of pinch devices