Analysis of Turbulence in Fusion Plasmas

Turbulence in magnetically confined fusion plasmas is an intellectually challenging subject. Understanding it is an important issue on the long road to fusion energy as a power source for humanity, as turbulence both limits the performance of future reactors and is behind extraordinary and potentially beneficial confinement bifurcations. Fusion plasmas are extreme, strongly driven systems, far from thermodynamic equilibrium, in which turbulence plays a major role. They are characterised by a broad range of unusual phenomena caused by the interaction between turbulence and the intense confining magnetic field, some of which are still poorly understood. The resulting complex systems, characterised by emerging structures on a broad range of temporal and spatial scales, require specific and advanced analysis and modelling tools.

This book reviews some of the observations that reveal the complex nature of plasma turbulence in detail and explains their implications. The change in paradigm needed to understand the observations is then discussed and mathematical models are highlighted that might address the dynamics better than traditional models. Along the way, a range of advanced analysis tools needed to characterize turbulence in this complex regime are presented and illustrated, including non-linear analyses, causality, and intermittence. The book aims to stimulate their broader adoption for the analysis of data from both experiments and numerical turbulence simulations.