On the dependence of energy confinement on elongation in single null divertor plasmas

An analysis of the effect of magnetic geometry on heat flux in a wide range of single null diverted discharge configurations with 1.5 < κ(95) < 2.2, 0.2 < δ(95) < 0.45 suggests that elongation is beneficial for confinement. If heat diffusivities are assumed not to depend on plasma shape., the predicted exponent for a power law scaling with elongation is alpha(kappa) approximate to 0.74, based on the configurations in the study. This is very close to dependences from the ITER database for discharge conditions, such as ELM H-modes, obtained from a large number of experiments in various tokamak devices.