Thermal effects of divertor sweeping in ITER

Thermal effects of magnetically sweeping the separatrix strike point on the outer divertor target of the ITER are calculated. For the 0.2 Hz*+or-12 cm sweep scenario proposed for ITER operations, the thermal capability of a generic target design is found to be slightly inadequate (by approximately 5%) to accommodate the full degree of plasma scrape-off peaking postulated as a design basis. The principal problem identified is that the 5-s sweep period is long relative to the 1.4-s thermal time constant of the divertor target. An increase of the sweep frequency to approximately 1 Hz is suggested; this increase would provide a power handling margin of approximately 25% relative to present operational criteria.<>