Recent fully non-inductive operation results in Tore Supra with 6 min, 1 GJ plasma discharges

The experimental programme of Tore Supra, the largest superconducting tokamak in the world ( a = 0.72 m, R = 2.4 m, I p < 1.7 MA, B T < 4.5 T) was devoted in 2003 to studying the heat removal capability and particle exhaust in steady-state fully non-inductive current drive discharges simultaneously. This required both advanced technology integration and steady-state real-time plasma control. In particular, an improvement of the plasma position to within a range of few millimetres, and new real-time controls of radio frequency power and various actuators built around a shared memory network, have allowed Tore Supra to access a powerful steady-state regime with an improved safety level for the actively cooled plasma facing components. Feedback controlled fully non-inductive plasma discharges have been sustained in a steady-state regime for up to 6 min with a new world record for injected–extracted energy exceeding 1 GJ. Experimental results and an analysis of the physics involved in these discharges are reported and discussed.