On the correlation between density profile and particle flux in H-mode tokamak plasmas and the implication for ITER

Density peaking in tokamak ELMy H-mode plasmas is studied using data from the Joint European Torus (JET). It is shown that the electron density gradient and electron particle flux at mid-radius are correlated when these two quantities are normalized to their heat-power-balance counterparts. Therefore, the density profiles cannot be considered canonical and particle sources should be taken into account when extrapolating the density profiles to the ITER next-step device. The relation between density and temperature gradients at mid-radius is predicted in the range of (∇ n e / n e )/(∇ T e / T e ) ∼ 0.15–0.35 for plasmas with safety factor and collisionality similar to ITER standard discharge.