Edge localized modes (ELMs), that are present in most tokamak H- (high confinement) modes, can cause significant damage to plasma facing components in fusion reactors. Controlling ELMs is considered necessary and hence it is vital to understand the underlying physics. The stability of ELMs is typically expressed in terms of the pressure gradient ∇p in the edge and the edge current density jϕ. Both ∇p and jϕ are usually derived from profiles fitted to the measured edge density and temperature profiles, where for the calculation of jϕ neoclassical theory is used.This paper presents direct measurements of the magnetic pitch angle γm evolution in the edge and the derived jϕ. These provide a method to validate the jϕ as derived with neoclassical theory and they open up the possibility to find a complete, self-consistent set of edge profiles, that fit density, temperature and γm measurements, hence allowing for a more accurate stability analysis.
Self-consistent core-pedestal ITER scenario modeling