This Roadmap article addresses the critical and multifaceted challenge of plasma-facing component (PFC) damage caused by runaway electrons (REs) in tokamaks, a phenomenon that poses a significant threat to the viability and longevity of future fusion reactors such as ITER and DEMO. The dramatically increased RE production expected in future high-cu…
We report the observation and analysis of ion cyclotron emission (ICE) in the Wendelstein 7-X (W7-X) stellarator during discharges without a significant fast-ion population. In these experiments, ICE is observed using the strap of the ICRF antenna, while remaining undetectable on the B-dot probes during ECRH-only phases. At low electron densities, …