Peculiarity of highly radiating multi-impurity seeded H-mode plasmas on JET with ITER-like wall

On JET with fully metallic first wall, highly radiative conditions with N-2, Ne and Ar as well as their mixture as radiators are approached in high density H-mode plasmas. The confinement increases from H-98( y,H-2) =.0.65 in unseeded pulses with gamma(rad) similar to 30% to a value of H-98(y,H-2)=.0.75 at gamma(rad) similar to 50% with N-2 injection. A degradation of the pedestal profile is compensated by steeper core ne and Te profiles. Further increase of gamma(rad) with increase of the N-2 seeding rate leads to a moderate confinement degradation which can be avoided by applying of combined impurity seeding. The enhancement of the plasma performance for the radiation fractions beyond 55% with the maximum value of H-98(y,H-2) = .0.78 is reached with combined N-2 + Ne and N-2+ Ar impurity injections. The observed intense, strongly localized radiation at the X-point inside the confined plasma in the scenarios with the highest radiated power fraction is interlinked to complete divertor detachment. In the JET-ILW, the X-point radiation is stable, reproducible and reversible.