G. Grieger

TL;DR: The W7•AS experiment as discussed by the authors has successfully demonstrated two aspects of advanced stellarators, the improved equilibrium and the modular coil concept, which can best be realized with a modular coil system.

TL;DR: In this article, the Wendelstein VII-X experiment at the Max-Planck-Institut fur Plasmaphysik has been used to demonstrate the capability of the modular stellarator line to achieve quasi-steady-state operation in a temperature regime > 5 keV.

TL;DR: Wendelstein 7-AS was the first modular stellarator device to test some basic elements of stellarator optimization: a reduced Shafranov shift and improved stability properties resulted in β-values up to 3.4% as discussed by the authors.

TL;DR: Substantial progress was made during the period 1981-1986 in plasma parameters, physics understanding, and improvement of the stellarator/heliotron concept as discussed by the authors, and the short-term direction of the program is clear; a number of new facilities that were designed to resolve these issues are about to come into operation or are in the final design stages.