A novel approach for estimating turbulent transport coefficients in fusion devices is presented. The diagnostic method is established on the analysis of the conditional variance of one-point time series of density or temperature fluctuations. It is tested on data obtained from probe measurements in the edge of the tokamak ASDEX Upgrade and the stellarator Wendelstein 7-X, and on synthetic data from the gyrofluid transport model GEMR. The approach demonstrates a remarkable degree of accuracy, typically within a factor of two of the actual transport measured by more difficult means. It is a simple and accurate way of evaluating turbulent particle and heat transport coefficients that does not require measurements of the velocity fluctuations.
This paper presents a novel approach to accurately estimate turbulent transport coefficients in fusion devices using the conditional variance of density or temperature fluctuations. The method is tested on data from ASDEX Upgrade and Wendelstein 7-X, and shows good agreement with more complex measurements, making it a simple and effective way to evaluate particle and heat transport.