START-UP OF THE OHMIC PHASE IN JET.

Abstract

JET has been designed to permit the study of plasmas in which alpha -particle heating is a significant part of the power balance. This paper describes the stages of plasma formation, current rise and Ohmic flat-top. The sections on plasma formation describe the physical processes that dominate this stage, the strategy that was adopted to obtain the correct fields at breakdown, the operating range and effects of an excessive stray magnetic field. The sections on the current-rise and flat-top examine current penetration and stability during the rise phase, density control, particle confinement, the flat-top operating diagram, flux consumption and energy confinement. Finally, the conclusions of the study will be presented.