Errors and limits in the determination of plasma electron density by measuring the absolute values of the emitted continuum radiation intensity

Abstract

The reliable determination of a plasma electron density structure requires a good knowledge of the errors affecting the employed technique. We have used a technique based on the measurement of the absolute light intensity emitted by travelling plasma structures in plasma focus devices, but it can be easily modified to other geometries and even to stationary plasma structures with time-varying plasma densities. The purpose of this work is to discuss in some detail the errors and limits of this technique. Three separate errors are shown: the minimum size of the density structure that can he resolved, an overall error in the measurements themselves, and an uncertainty in the shape of the density profile.