EUROfusion Tokamak ExploitationMAST-U TeamRivero-Rodriguez, J. F.McClements, K. G.Fitzgerald, M.Sharapov, S. E.Cecconello, M.Crocker, N. A.Dolby, I.Dreval, M.Fil, N.Galdon-Quiroga, J.Garcia-Munoz, M.Blackmore, S.Heidbrink, W.Henderson, S.Jackson, A.Kappatou, A.Keeling, D.Liu, D.Liu, Y. Q.Michael, C.Oliver, H. J. C.Ollus, P.Parr, E.Prechel, G.Rhodes, T.Ryan, D.Shi, P.Vallar, MatteoVelarde, L.Williams, T.Wong, H.2024-07-032024-07-032024-07-032024-08-0110.1088/1741-4326/ad56a2https://infoscience.epfl.ch/handle/20.500.14299/209167WOS:001253509300001MAST-U is equipped with on-axis and off-axis neutral beam injectors (NBI), and these external sources of super-Alfv & eacute;nic deuterium fast-ions provide opportunities for studying a wide range of phenomena relevant to the physics of alpha-particles in burning plasmas. The MeV range D-D fusion product ions are also produced but are not confined. Simulations with the ASCOT code show that up to 20% of fast ions produced by NBI can be lost due to charge exchange (CX) with edge neutrals. Dedicated experiments employing low field side (LFS) gas fuelling show a significant drop in the measured neutron fluxes resulting from beam-plasma reactions, providing additional evidence of CX-induced fast-ion losses, similar to the ASCOT findings. Clear evidence of fast-ion redistribution and loss due to sawteeth (ST), fishbones (FB), long-lived modes (LLM), Toroidal Alfv & eacute;n Eigenmodes (TAE), Edge Localised Modes (ELM) and neoclassical tearing modes (NTM) has been found in measurements with a Neutron Camera (NCU), a scintillator-based Fast-Ion Loss Detector (FILD), a Solid-State Neutral Particle Analyser (SSNPA) and a Fast-Ion Deuterium-alpha (FIDA) spectrometer. Unprecedented FILD measurements in the range of 1-2 MHz indicate that fast-ion losses can be also induced by the beam ion cyclotron resonance interaction with compressional or global Alfv & eacute;n eigenmodes (CAEs or GAEs). These results show the wide variety of scenarios and the unique conditions in which fast ions can be studied in MAST-U, under conditions that are relevant for future devices like STEP or ITER.Physical SciencesFusionSpherical TokamakFast-Ionstext::journal::journal article::research article