Plasma-surface interactions in tokamaks

TLDR

Plasma–surface interactions in tokamaks encompass ion recycling, low‑Z and high‑Z contaminant release, and their effects, and the current state of research is summarized in this review. The review focuses on how these surface interactions influence present‑day tokamak discharges and future fusion reactors. It surveys the underlying physical processes, particle‑beam measurement data, and control methods for mitigating surface interaction effects.

Abstract

A summary is given of the present status of research on plasma-surface interactions in tokamaks. Three groups of important interactions are considered: recycling of the principal ion species, usually hydrogen or deuterium; the release and effect of low-Z contaminants; and the release and effect of high-Z contaminants. In each case the basic physical processes are reviewed and the relevant data from particlebeam measurements are summarized. Emphasis is given to discussing the effect of the various surface interactions in present-day tokamak discharges and in future fusion reactors. Surface studies in tokamaks are reviewed and methods of controlling the surface interactions and their effects are considered.