Level crossings, excess times and transient plasma-wall interactions in fusion plasmas

TL;DR

This paper develops a stochastic model to predict plasma-wall interactions in fusion devices by analyzing level crossing rates and excess times of boundary plasma fluctuations, offering new insights into transient transport events.

Contribution

It introduces a novel stochastic framework to quantify transient plasma-wall interactions based on level crossing analysis in fusion plasmas.

Findings

Derived an expression for level crossing rate from joint distribution.

Predicted average time plasma spends above threshold levels.

Provided new insights into plasma-wall interaction dynamics.

Abstract

Based on a stochastic model for intermittent fluctuations in the boundary region of magnetically confined plasmas, an expression for the level crossing rate is derived from the joint distribution of the process and its derivative. From this the average time spent by the process above a certain threshold level is obtained. This provides novel predictions of plasma-wall interactions due to transient transport events associated with radial motion of blob-like structures in the scrape-off layer.