Comment on ‘Deuterium supersaturated surface layer in tungsten: ion energy dependence’

Abstract

This comment examines a recent study claiming the observation of deuterium (D) supersaturated surface layer (SSL) in tungsten samples exposed to D plasma in the PISCES-A plasma device at ion energies as low as 45 eV/D (Nishijima et al 2023 Nucl. Fusion 63 126003). Applying SDTrimSP simulations and recalling the previous study on SSL formation, herein we want to emphasize that the proposed model in the mentioned paper relies on a number of strong assumptions and that many of the observations made can be more easily rationalized by the presence of impurities. The present comment will be conducive to avoid some possible misunderstanding on the SSL formation mechanism.

Keywords

• deuterium supersaturated surface layer (DSSL)
• low-energy plasma exposure
• tungsten surface
• displacement threshold