From W7-X to a HELIAS fusion power plant: On engineering considerations for next-step stellarator devices

With the recent start of operation of Wendelstein 7-X (W7-X), the helical-axis advanced stellarator concept (HELIAS) has gained renewed attention. In particular a discussion has been started about a research strategy leading from W7-X to a commercial HELIAS fusion power plant. In order to bridge the respective gap in physics and technology between those devices, concepts for an intermediate-step burning plasma stellarator are under discussion. Recent studies have focused on physics issues of importance to such devices. Extending this discussion, engineering and technology considerations for next-step HELIAS devices are discussed in this work.