Scaling of the scrape-off layer width during inter-ELM H modes on MAST as measured by infrared thermography

TL;DR

This study measures the scrape-off layer width during inter-ELM H modes on MAST using infrared thermography, providing insights into heat flux scaling critical for future fusion devices like ITER.

Contribution

It offers new empirical measurements of the SOL width during specific plasma conditions on MAST, informing heat flux predictions for reactor design.

Findings

SOL width can be as small as 1 mm during inter-ELM H modes

Empirical scalings of heat flux width are supported by measurements on MAST

Results aid in predicting divertor heat loads for future reactors

Abstract

The power load to the divertor surfaces is a key concern for future devices such as ITER, due to the thermal limits on the material surface. One factor that characterizes the heat flux to the divertor is the fall off length in the scrape-off layer (SOL), which recent empirical scalings have shown could be as small as 1 mm. These predictions are based on a multi-machine scaling of the heat flux width fitted using an expression for the divertor heat flux profile which includes a term for the exponential decay in the SOL and diffusion about the last closed flux surface (LCFS) in the private flux region.