Interpretation of impurity confinement time measurements in Tokamaks

An analysis techniques for interpreting impurity confinement time data is presented. If chord-averaged temporal evolutions of injected impurity spectra are employed in an impurity transport experiment, they are normally used to obtain impurity confinement times. The authors have established experimentally that this type of data often has characteristics which justify its use in conjunction with a simple analytical model to evaluate the constant diffusion coefficient and the constant convective velocity in an impurity transport flux which is the sum of diffusive and convective terms. Since this is often the goal of numerical simulation analysis, the technique may substitute for data-intensive numerical modelling.