Fusion glossary
H
The H-mode is the baseline mode of plasma operation on all of today's major tokamaks. As the plasma auxiliary heating exceeds a certain threshold power the energy confinement of the plasma spontaneously doubles. This phenomenon was first discovered on ASDEX in 1982.
Ash is the name given to the helium nuclei produced by fusion reactions in a deuterium-tritium plasma. Once the helium nuclei have shared their energy with the rest of the plasma they have no further use; their removal and replacement by deuterium-tritium fuel is required to prevent dilution of the plasma.
A concrete-shielded chamber with a controlled atmosphere that can be used to work on radioactive materials and components with a view to repairing them and refurbishing them for future re-use, or dismantling them for disposal. The chamber is equipped with remote manipulators or robotic devices for this purpose. No human access is foreseen.