COMPATIBILITY OF H-MODE WITH A RADIATING BOUNDARY AND DIVERTOR DETACHMENT

ITER or any other future fusion device will operate in H-mode to take advantage of the improved confinement. Stationary operation in H-mode, however, requires the occurrence of ELMs, and the resulting power loa d on the divertor target plates is not acceptable from the engineering point of view. Beyond this, the present divertor concepts rely on a c old and dense (possibly detached) divertor plasma. Large type-I ELMs, however, carry tao large a power and possibly burn through such cold d ivertor plasmas. The completely detached I-I-mode (CDH-mode), recently established in ASDEX Upgrade shows detachment at both divertor target plates and small ELMs (so-called type-III ELMs), that do not burn thr ough the divertor plasma. The extrapolation of this scenario to ITER, however, is an important question.