Improved ERO modelling for spectroscopy of physically and chemically assisted eroded beryllium from the JET-ILW☆

Highlights: • The earlier modelling results [D. Borodin et al., Phys. Scr. T 159, 014057 (2014)] were revisited due to the new background plasma input which reasonability was proved by Be II line ratios, D spectroscopy and BeD reaction branching ratios. • The reproducing of the sightline integrated passive spectroscopy near the inner wall guard limiter fabricated from solid beryllium (Be) has proved the 'ERO-min' fit for physical sputtering yields for Be at plasma-wetted areas. • The angle and energy distributions of sputtering ions on impact influencing the effective local erosion yields were generated using the recently developed analytical expressions. • The detailed shadowing pattern of the limiter surface simulated by the PFCFlux code was incorporated into ERO and used in the simulations. • The BeD release and light emission plume was first time simulated by ERO for the JET ILW application. The BeD light emission (sightline integrated) trend and absolute value during the plasma density scan were reproduced well (∼20%). - Abstract: Physical and chemical assisted physical sputtering were characterised by the Be I and Be II line and BeD band emission in the observation chord measuring the sightline integrated emission in front of the inner beryllium limiter at the torus midplane. The 3D local transport and plasma-surface interaction Monte-Carlo modelling (ERO code [18]) is a key for the interpretation of the observations in the vicinity of the shaped solid Be limiter. The plasma parameter variation (density scan) in limiter regime has provided a useful material for the simulation benchmark. The improved background plasma parameters input, the new analytical expression for particle tracking in the sheath region and implementation of the BeD release into ERO has helped to clarify some deviations between modelling and experiments encountered in the previous studies [4], [5]. Reproducing the observations provides additional confidence in our 'ERO-min' fit for the physical sputtering yields for the plasma-wetted areas based on simulated data.