Cooling water calorimetry measuring results from the first years of ASDEX Upgrade operation

At the tokamak ASDEX Upgrade an extensive cooling water calorimetry system was installed. This system has measured the toroidal and poloidal distributions of the energy deposition by monitoring the temperature rise of the cooling water in 80 separate cooling units in the divertor plates and the central heat shield. The measurements show, that there exist no toroidal asymmetries in the energy deposition on the divertor plates for all kinds of ohmic discharges and for ICRH discharges with a toroidal magnetic field directed opposite to the plasma current. However, Neutral Beam Injection causes a toroidal asymmetric energy deposition profile. Furthermore the reduction of the poloidal in-out asymmetry of the energy load at the divertor plates due to magnetic field reversion was detected. Making up the general energy balance of ASDEX Upgrade, adding the energy detected by the cooling water calorimetry system and the radiation loss energy measured by the bolometry diagnostic, one gets 92%-97% of the energy input. (orig./HD)