Scaling of Confinement with Isotopic Content in Deuterium and Tritium Plasmas
Authors: C.K. Phillips, S.D. Scott, et al
The scaling of the electron thermal diffusivity, ce, with relative gyro radius, r*, has been measured on TFTR by comparing nearly identical ICRF-heated discharges which differ only in hydrogenic isotopic content. Contrary to the gyro-Bohm scaling (ce ~ cBr*, where cB is the Bohm diffusivity) observed on DIII-D when r* was varied through a scan of magnetic field strength, ce is found to scale inversely with r*. Hence, global energy confinement is 8-11% higher in deuterium-tritium plasmas than in deuterium only plasmas, with the higher stored energy attributed almost entirely to the electrons.