Influences of edge localized mode-like pulsed plasma bombardment on deuterium retention in tungsten

Abstract

Deuterium (D) retention in tungsten (W) subjected to pulsed D plasma bombardment (surface absorbed energy density Q∼0.5–0.7 MJ m−2 at ∼0.3–0.5 ms) has been investigated in a magnetized coaxial plasma gun. A high temperature desorption peak of D2 appears at ∼1000–1100 K following transients at ∼0.5 MJ m−2. At a higher Q∼0.7 MJ m−2, the total amount of D retained in W is significantly reduced. Nano-sized helium (He) bubbles, created by steady-state He plasma pre-exposure at ∼573 K, slightly lower D retention, while a significant reduction is observed for a W fuzzy surface formed by steady-state high temperature (∼1100 K) He plasma pre-exposure.