Session 6P - TEXT-U, Tore Supra, HBT-EP, and Other Tokamaks.
POSTER session, Wednesday afternoon, November 13
Exhibit Hall - Concourse Level, Adam's Mark
We use a set of discrete saddle coil pairs, two high-power amplifiers, and signals derived from plasma diagnostics to create a feedback system for MHD mode control. A new digital signal-processing (DSP) system will be used to test various feedback techniques. HBT-EP's present experimental configuration uses five modular saddle coil pairs, mounted to approximate a single-phase, m=2, n=1 helical winding. The DSP hardware is based on the Analog Devices ADSP-21060 chip, providing 40 MIPS. Eight A/D and four D/A channels allow processing at a 100 kHz rate. Magnetic and soft x-ray diagnostics provide reference signals for feedback calculations. The design and construction of the DSP system are discussed, and we report initial results using phase-sensitive algorithms. Future experiments will investigate multiple phase and multiple helicity magnetic feedback. \smallskip \(^*\)Work supported by US DOE Grant: DE--FG02--86ER--53222.