On-line prediction and mitigation of disruptions in ASDEX Upgrade

An on-line predictor of the time to disruption has been installed onthe ASDEX Upgrade tokamak. It is suitable either for avoidance of disruptions or for mitigation of those that are unavoidable. The prediction uses a neuralnetwork trained on eight plasma parameters and their time derivatives extractedfrom 99 disruptive discharges. The network was tested off-line over 500 discharges and was found to work reliably and to be able to predict the majority of the disruptions.The trained network was installed on-line, testedover 128 discharges and used to inject killer pellets to mitigate the disruption loads.