On the effect of negative triangularity on ion temperature gradient turbulence in tokamaks

Abstract

Considering the same magnetic equilibrium and plasma conditions as in Duff et al. [Phys. Plasmas 29, 012303 (2022)], we perform linear and nonlinear simulations of electrostatic ion temperature gradient turbulence investigating the role of triangularity δ. Differently from what was previously reported, we find that triangularity increases the transport level regardless of its sign, but more strongly when δ is positive. For the case analyzed, we identify the shear of triangularity as the critical parameter determining the transport level, indicating that even in the local limit negative triangularity can reduce the transport efficiently, suggesting that confinement improvement can also be expected for larger devices.