Integrated modelling for tokamak plasma: Physics and scenario optimisation

Simulations of JET and AUG HS with the GLF23 model show that the observed core confinement improvement can be partly explained by the beneficial s/q effect on the ITG driven transport while the effect of the ExB shear stabilisation is weaker than in H-mode plasmas. Strong stabilising effect of βe on the ITG turbulence has been found, but the transport reduction due to this effect can be limited by the onset of the KBM mode at high βe. The simulations of toroidal rotation in HS with the GLF23 model give an indication of the toroidal momentum pinch (Pr<1). Use of H-mode parameters in the GLF23 and BgB models results in the over-peaking of the density profile while the temperatures are sufficiently accurately predicted. Based on the performed analysis a retuning of the BgB [7] and GLF23 models which enables a more accurate prediction for the main heating phase of HS is suggested. An impact of the models modifications on the predictions for ITER HS is to be assessed. The current ramp up and ramp down [2] phases are satisfactorily predicted with the original Lmode version of the BgB model. During the main heating phase the pedestal height and width are in a good agreement with the EPED model [9]. The modelling of ITER HS based on the results presented here, as well as the scenario optimisation will be discussed in Ref. 14.