Particle transport modelling for D/T ratio control experiments in JET

This study presents results from particle transport modelling for D/T ratio control experiments conducted during the JET DTE3 campaign. TRANSP interpretative and JETTO predictive simulations for D and T densities were performed and their results are discussed. Despite using simplified models based on Bohm-gyroBohm transport, the simulations incorporate self-consistent sources and impurities and cover the full radial range. The simplified models effectively reproduced the evolution of electron density and neutron rates. However, the predicted D/T ratio evolution responded to control requests faster than what was experimentally observed, suggesting that the employed models possess certain limitations. Specific cases involving swapped gas injection species were also studied, highlighting the potential applicability of the proposed methodology in future experimental scenarios. TRANSP interpretative analysis indicates that a Real-Time (RT) scheme employing simplified quasi-neutrality and Zeff estimations can be implemented with high degree of reliability. JETTO predictive analysis suggests that a simplified modelling approach for the behaviour of the future RT controllers of D/T mixture can be effective. Such an approach involves using measured temperatures, omitting explicit modelling of the SOL physics, and adopting simplified assumptions for the particle transport.