Li-filled CPS targets under normal and oblique transient plasma loads in QSPA

• Li-filled SLM W-CPS targets tested in QSPA under 0.25 ms transient pulses. • Particle ejection threshold identified near 1.2 MJ m −2 ; negligible particle emission below 0.25 MJ m −2. • Velocities of particles ejected from the exposed surfaces of 1–33 m s −1 were observed, persisting for > 7 ms after PSI onset. • After 50 pulses at ∼ 3 MJ m −2 , normal incidence showed no visible W substrate damage. • Damage to the leading edge is a crucial factor determining the resilience of the target exposed to inclined transient plasma. The erosion behaviour of selective laser melting (SLM) tungsten Capillary Porous Structure (CPS) targets filled with lithium (Li) was investigated in the Quasi-Stationary Plasma Accelerator (QSPA) under transient plasma loading. Plasma pulses (0.25 ms, ∼3 MJ/m 2 ) were applied to two CPS targets, one oriented normally and the other inclined relative to the incident plasma stream. High-speed observations of plasma-surface interaction showed that particle release from the surface was strongly governed by the incident energy density. Low-energy exposures (<1.2 MJ/m 2 ) resulted in only minor particle release, whereas higher loads led to significant ejection with velocities up to 33 m/s. Post-mortem analysis of the CPS target under oblique plasma exposure revealed erosion at the leading edge, pointing to this region as a critical factor in target resilience. In addition, Li- and Sn-filled CPS samples were compared under both normal and inclined irradiation in regimes representative of fusion-relevant transient events.