Fast-ion and runaway-electron physics in reactor-relevant fusion plasmas

Project title: Fast-ion and runaway-electron physics in reactor-relevant fusion plasmas
Main applicant: Marco Cecconello, Applied Nuclear Physics
Co-applicant: Jacob Eriksson, Applied Nuclear Physics
Grant amount: SEK 4 200 000 for the period 2027-2030

A key element of a fusion reactor is the self-heating from the α-s from DT fusion reactions. The 3.5 MeV α-s are much more energetic than the fuel ions (tens of keV), and this helps sustaining the high temperatures required for fusion burning plasmas. Reaching self-heating, however, requires external auxiliary heating and current drive delivering several tens of MW of power to the plasma either by Neutral Beam Injection (NBI), giving rise to ions with energies up to 1 MeV or by radio-frequency heating which rise the ion end electrons energies into the MeV range. In addition to fusion born α-s and particles from auxiliary heating, runaway electrons (REs) produced during disruptions can reach relativistic energies. All these supra-thermal particles have the potential to be detrimental to the performance and integrity of a fusion reactor either by damaging the wall (α-s and REs) or by driving MHD instabilities (α-s and fast ions). The aim of this project is to combine experimental observations of these supra-thermal particles, interpretative modelling based on reduced transport models (TRANSP/NUBEAM) and predictive modelling using the hybrid non-linear extended MHD-kinetic (JOREK) and the kinetic-fluid DREAM codes to study (i) the non-linear interaction between fast ions and MHD instabilities in spherical and (ii) conventional tokamaks (MAST Upgrade, JT-60SA) in ITER relevant scenarios and the impact of REs during Electron Bernstein Wave heating & current drive in MAST Upgrade.