Technical concept of the dynamic ergodic divertor for TEXTOR 94

For ergodization and rotation of the plasma edge region it is proposed to install a set of 16 helical coils on the inboard side of the liner in the vacuum vessel of TEXTOR 94. The coils will be fed by a 4-phase (rotating) current with a peak value of 15 kA. The system is optimized for the following four frequencies: DC, 50 Hz, 1 kHz, and 10 kHz. To reduce the skin effect the coil conductor consists of 42 insulated wires. Each coil is enclosed in a stainless steel tube of 0.2 mm thickness. The maximum coil temperature is 200/spl deg/C, and the coolant is water at a pressure of 2.5 MPa. The coils will be supplied by eight switch mode power supply units with IGBT technology. A transformer matches the power supply to the coil parameters. The reactive power is compensated. Operation with DC-current is made possible by use of additional rectifiers.