An advanced plasma control system for the DIII-D tokamak

An advanced plasma control system is being implemented for the DIII-D tokamak utilizing digital technology. This system will regulate the position and shape of tokamak discharges that range from elongated limiter to single-null divertor and double-null divertor with elongation as high as 2.6. Through use of a control algorithm which can be varied in real time this system is expected to provide more precise control of the DIII-D discharge shape than is possible in the analog control system presently in use. In addition to shape control the system will provide a platform for research on real-time optimization of discharge performance. A relatively simple design has been achieved through the use of a small number of very-high-speed digital processors coupled with high-speed data acquisition hardware. The frequency response is expected to be adequate to control the unstable vertical motion of highly elongated discharge shapes