Magnetic configuration sweep control in Heliac type stellarators

Abstract: A novel magnetic configuration sweep control system for the TJ-II Heliac device is described. The system is prepared to establish a reference for plasma, torus or vessel current while the coil configuration currents are swept during a single plasma discharge. It can also be run in a special simulation mode, which does not require powering the TJ-II device, intended for commissioning and experiment preparation purposes. Preliminary tests with the system have shown its ability to perform rotational transform scans while establishing a waveform for torus current independently, despite variable plasma conditions. This opens up new experimental possibilities to study the influence of rotational transform and shear independently.