EFDA-JET-CP(03)01/39
EDA H-mode Pedestal Identity Studies on JET and Alcator C-Mod
The "enhanced Da" (EDA) H-mode developed on Alcator C-Mod is a high density, quasi stationary state with good confinement but no large ELMs, therefore potentially suiting ITER standard operation. Initial studies of it on JET did not recover the regime, but plasma conditions particularly in the edge pedestal remained far from those typical for C-Mod. The definitive test of reproducibility of tokamak plasma behaviour is provided by repeating identical values of the dimensionless variables n*e, r*, b, Zeff (normalized collisionality, Larmor radius, pressure and effective charge), since its essential physics can be written as functions of only these quantities, plus magnetic equilibrium parameters e a / R0, k, d, q (inverse aspect ratio, elongation, triangularity and safety factor) defining the specific geometry.