Search

A method has been proposed to study heat transport in magnetically confinement plasmas, based on the transfer entropy (TE). In this work, we study this method by introducing perturbations in simulations made using a resistive Magneto-HydroDynamic model. The evolution of radial heat transport is monitored using the TE, and these results are used to compute an effective heat diffusivity. This effective diffusivity is then compared to estimates from other methods. The analysis is applied to several numerical simulations and in various radial ranges. It is shown that the transfer entropy is a suitable technique to analyze heat transport and evaluate an effective diffusivity in fusion plasmas. [ABSTRACT FROM AUTHOR]

This work uses the outward propagation of spontaneously generated fluctuations of the electron temperature to study heat transport in the TJ-II stellarator. Data from a set of experiments in which the heating power was scanned systematically are analyzed using the transfer entropy. The transfer entropy graph suggests there are at least two modes or channels of propagation: one channel is continuous, reminiscent of diffusion, while the other is non-local, activated mainly when the heating power is large. When the heating power is increased, the region of non-locality expands outwards, leading to the ubiquitously observed deterioration of confinement with heating power. [ABSTRACT FROM AUTHOR]

A set of new criteria for the diagnosis of the possible occurrence of a large blackout are constructed, using the output from a model for the dynamics of the electric power grid (the OPA model). The approach used is to look for maximum values of the Transfer Entropy between time series of the system variables and the time series of large blackouts. The best criterion is found by looking at the number of overloaded lines at the beginning of the day. [ABSTRACT FROM AUTHOR]