REAL-TIME PROTECTION OF THE OHMIC HEATING COIL FORCE LIMITS IN DIII-D

The maximum safe operating limits of the DIII-D tokamak are determined by the force produced in the ohmic heating coil and the toroidal fiel d coil during a plasma pulse. This force is directly proportional to t he product of the current in the coils. Historically, the current limi ts for each coil were set statically before each pulse without regard for the time varying nature of the currents. In order to allow the ful l time-dependent capability of the ohmic coil to be used, a system was developed for monitoring the product of the currents dynamically and making appropriate adjustments in real time. This paper discusses the purpose, implementation, and results of this work.