Fostering Faster Vent Recovery Times in C-2W Using Glow Discharge Cleaning

Restoring wall conditions in C-2W (Norm)—TAE Technologies’ present fusion device—after a vent is critical to produce high quality field-reverse configuration (FRC) plasmas. Facilitating vent recovery in C-2W is a multiphase process requiring strict levels of cleanliness during vent periods to minimize the number of contaminants introduced into its interior. To restore vessel wall conditions, a non-evaporable getter system and a cryogenic pumping system are used, quickly reducing base pressures to 1e-9 Torr [1]. To complement these existing systems, a hydrogen-based glow discharge cleaning (GDC) system was commissioned and tested for the first time in C-2W. Partial pressure data collected during experimentation indicated effective removal of water and hydrocarbons from the near surface of the confinement vessel. While experimentation is required to assess the impact of GDC on machine recovery time, a comparison of preliminary spectroscopic data with past recovery periods reveals lower initial carbon and oxygen impurity intensities. Anticipated future GDC experimentation in C-2W will explore alternative gases and gas mixtures and system expansion to machine divertors.

[1] H. Gota et al 2021 Nucl. Fusion 61 106039