Use of Actuator management in ASDEX Upgrade control

The control experiments on ASDEX Upgrade so far were only able to use one gyrotron per controller to perform a control action (for example supply power for Te control). The power provided by one gyrotron is not sufficient for the control tasks described below. In order to overcome this issue, we have introduced a virtual actuator which combines arbitrary number of gyrotrons and is responsible for the controller command distribution. The concept of the virtual actuator is described in [1]. This contribution will discuss the use of the virtual actuator in the ASDEX Upgrade experiments, where it proved to be a powerful and useful method. The first application of the virtual actuator is the ßp control in the I-mode experiment. In this case, ßp was controlled by a group of gyrotrons combined to a virtual actuator heating the plasma center.