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 (R0 = 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 delT(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 = 2tau(E)OMEGA) is observed in low-density, low-current plasmas when the ECRH power is comparable to the ohmic input power.