Small ELM regimes with good confinement on JET and comparison to those on ASDEX Upgrade, Alcator C-mod and JT-60U

Since it is uncertain if ITER operation is compatible with type-l edge localized modes (ELMS), the study of alternative ELM regimes is an urgent issue. This paper reports on experiments on JET aiming to find scenarios with small ELMS and good confinement, such as the type-II ELMS in ASDEX Upgrade, the enhanced D-alpha H-mode in Alcator C-mod or the grassy ELMS in JT-60U. The study includes shape variations, especially the closeness to a double-null configuration, variations of q(95), density and beta poloidal. H-mode pedestals without type-I ELMs have been observed only at the lowest currents (