Specialist Physics Seminar Wednesday 17 April 2002


Role of q profile in the Transport Barriers formation on T-10 tokamak

Ksenia Razumova

Kurchatov Institute, Moscow, Russia



The role of radial q(r) profile in the transport barriers formation has been investigated on the T-10 tokamak.

The experiments with the rapid current ramp-up (2MA/s) during the stationary off-axis ECR plasma heating have been conducted. It was shown that the electron internal transport barrier (e-ITB) in the plasma core is formed, when the core is shifted inward owing to the current ramp-up.

The e-ITB realization (increase of electron temperature gradient) begins with delay 10ms after the ramp-up start. This is sufficiently earlier than the additional current density could be able to penetrate in the barrier zone. The regimes with the single internal barrier; with single external barrier; and with simultaneous two barriers have been obtained.

The extremely important role of the MHD configuration during the e-ITB formation is emphasized. Additional on-axis ECR heating demonstrates that enhanced heat flux is also effective for the ITB increase near given resonance surface.