Liquid Metals As Plasma-Facing Materials For Fusion Energy Systems: Fundamental Studies of Deuterium Retention in Solid and Liquid Metals

Gaining a better understanding of density control will be important for optimizing and controlling high non-inductive current-drive fraction scenarios in future tokamaks. Lithium conditioning of the internal PFCs have been shown to pump hydrogenic species however contamination by residual gases is believed to limit its performance. A quantitative understanding of the influence of residual gases on the adsorption of deuterium by lithium will help the development of fusion energy. We propose to make fundamental measurements of D (deuterium) retention in solid and liquid metals using the new ultrahigh vacuum (UHV) surface analysis facilities being commissioned at PPPL. We will initially investigate ultrathin Li (lithium) films synthesized by controlled vapor deposition of Li metal onto various substrates. Pure Li films and Li films with surface contamination by residual gases typically found in tokamak vacuum systems will be studied.