Transport analysis in ohmic and ECR heated plasmas in the RTP tokamak

Global and local power balance studies in ohmic and ECR-heated plasmas in the RTP tokamak (R 0 =0.72 m, a=0.16 m, B T =2.14 T) are reported, and compared with models. In ohmic plasmas the energy confinement time is consistent with the Goldston-ohmic scaling law. Using ECRH, high T e and Del T e are obtained. An updated version of the Rebut-Lallia-Watkins transport model successfully describes chi e eff in these extreme plasma conditions. Improved confinement ( tau E ECRH =2 tau E Omega ) is observed in low-density, low-current plasmas when the ECRH power is comparable to the ohmic input power.