TFTR twenty year perspective

Deuterium-tritium plasmas (D-T) with core parameters almost identical to those expected in the core of ignited plasmas in ITER have served as a test bed to carry out the first detailed studies of D-T plasma physics including the first observations of alpha particle heating and alpha driven instabilities. TFTR operated above the original engineering design requirements and with high availability in D-T until experimental operation was terminated due to U.S. fusion budget cutbacks. A most valuable lesson learned was that D-T operation of a large experimental device is feasible as TFTR operation could have continued many more years while remaining within tritium and neutron activation limits. The flexibility and control of plasma parameters (e.g. plasma rotation) and the comprehensive diagnostic system enabled TFTR to make seminal contributions to tokamak plasma science such as first confirmation of the bootstrap current in a tokamak, detailed turbulence studies leading to a new paradigm for transport understanding, first observations of neoclassical tearing modes, and detailed measurements and modeling of plasma disruptions. Recent advances in understanding the fundamental processes controlling plasma transport provide new opportunities for improving tokamak plasma performance. Implementation of recent knowledge could lead to D-T operating regimes with strong alpha heating with modest extensions of the TFTR operating regimes