Negative triangularity scenarios: from TCV and AUG experiments to DTT predictions

Experiments, gyrokinetic simulations and transport predictions have been performed to investigate if a negative triangularity (NT) L-mode option for the DTT full power scenario would perform similarly to the positive triangularity (PT) H-mode reference scenario, avoiding the harmful edge localized modes (ELMs). The simulations show that if a beneficial effect of NT would not come from the edge-SOL region ?!"# > 0.9, one should renounce to part of the PT H-mode performance to avoid the ELMs. New dedicated experiments at TCV and AUG, with similar shapes and transport regimes, show that even with the small triangularity of the considered DTT scenarios, a beneficial effect of NT could come from ?!"# > 0.9, allowing NT L-modes to overperform corresponding PT L-modes, reaching central pressures comparable to larger power PT H-modes. For AUG, a similar central plasma performance is found with PT and NT for a PT/NT ELMy H-mode/H-mode couple of pulses and for a PT/NT non-ELMy H-mode/L-mode one, both with ECRH only. The beneficial effect of NT was shown by gyrokinetic runs to be due to an increase of the critical temperature logarithmic gradient when inverting the triangularity, with similar stiffness for positive and negative triangularity. The effect has been found in both ITG- and TEMdominant micro-instability regimes.