Effective Wall Conditioning in Rapid Development Fusion Devices: the C-2W case

Pioneering rapid concept implementation and high-paced design iteration, TAE's fusion program demands the continuous improvement of wall conditioning techniques to maintain ideal vacuum conditions for high performance operations and to facilitate vent recovery. To achieve these ends, C-2W (aka Norman) is equipped with a titanium arc deposition gettering system and a newly commissioned Glow Discharge Cleaning (GDC) system. In 2023, Norman's titanium deposition program adopted a new operational procedure from data based on MolFlow simulations and statistical analysis of localized wall pumping data from the confinement vessel and divertors. Additionally, two major vents included GDC, effectively removing hydrocarbons and residual water or hydrogenic species. To estimate and assess reactor wall pumping, fuel recycling, and impurity evolution, C-2W employs residual gas analyzers, spectroscopy-based diagnostic systems and daily neutral gas distribution experiments. This work presents comparative evidence of pump down curves, oxygen ion impurity spectroscopy transitions, and charge deposition on biasing electrodes, demonstrating the positive impact of wall conditioning recipes using GDC followed by titanium deposition. These new recipes reduced machine recovery time and promise further optimization, paving the way for faster, more efficient plasma operations.