Deuterium-Tritium Simulations of the Enhanced Reversed Shear Mode in the Tokamak Fusion Test Reactor
Authors: D. R. Mikkelsen, J. Manickam, S. D. Scott, et al.
The potential performance, in deuterium-tritium plasmas, of a new enhanced con nement regime with reversed magnetic shear (ERS mode) is assessed. The equilibrium conditions for an ERS mode plasma are estimated by solving the plasma transport equations using the thermal and particle dif- fusivities measured in a short duration ERS mode discharge in the Tokamak Fusion Test Reactor [F. M. Levinton, et al., Phys. Rev. Letters, 75 , 4417, (1995)]. The plasma performance depends strongly on Zeff and neutral beam penetration to the core. The steady state projections typically have a central electron density of ~2:5x10 20 m -3 and nearly equal central electron and ion temperatures of ~10 keV. In time dependent simulations the peak fusion power, ~25 MW, is twice the steady state level. Peak performance occurs during the density rise when the central ion temperature is close to the optimal value of ~15 keV. The simulated pressure profiles can be stable to ideal MHD instabilities with toroidal mode number n = 1;2;3;4 and ¥ for bnorm up to 2.5; the simulations have bnorm <2:1. The enhanced reversed shear mode may thus provide an opportunity to conduct alpha physics experiments in conditions similar to those proposed for advanced tokamak reactors.