Intermittent fluctuations at the boundary of magnetically confined plasmas

Abstract

This thesis presents a comprehensive analysis of a stochastic model for transport due to the motion of uncorrelated localized structures. The motivation for this model is found in the scrape-off layer (SOL) of magnetically confined plasmas, but its applicability extends to other turbulent or chaotic systems. This model provides a statistical framework to explore the implications of different transport mechanisms that dominate the SOL and predictions for the radial profiles of the lowest-order statistical moments. Additionally, the model can be used to develop improved methodologies for data analysis, particularly for velocity estimation of plasma fluctuations from imaging data. The model considers pulses with randomly distributed amplitudes, sizes, and velocities, moving radially with fixed shape and exponentially decaying amplitudes due to linear damping. Such a framework is pivotal in understanding the statistical properties and dynamics of blob-like structures in plasma, which significantly influence plasm