Integrated exhaust control with divertor parameter feedback and pellet ELM pacemaking in ASDEX Upgrade

An integrated exhaust scenario has been developed in ASDEX Upgrade providing simultaneous control of particle exhaust, time averaged divertor power flux and ELM power via pace-making of the ELM frequency. Feedback quantities are the divertor neutral flux (actuator: deuterium gas puff) and the divertor temperature as measured by thermoelectric currents (actuator: argon gas puff). The ELM frequency is stabilised to a level high enough for moderate ELM power load with repetitive injection of small pellets from the high field side. The scenario is fully compatible with the present tungsten wall coating, which constitutes about 65% of the area of the plasma facing components. It is intended for application in a future full-tungsten ASDEX Upgrade with strongly reduced intrinsic carbon radiation in order to simulate a possible full-tungsten stage of ITER.