PROFILE CONSISTENCY FEATURES IN SHAPED SAWTOOTHING OHMIC TCV PLASMAS

A large variety of plasma conditions has been created in TCV (Tokamak a Configuration Variable, B-T < 1.5 T, R-0 = 0.88 m, a < 0.25 m). They include limited and diverted discharges with elongations in the range 1-2.58, triangularities between -0.7 and 1 as well as 'square' shapes with plasma currents in the range 0.1-1 MA. Over the entire range of quasi-stationary ohmic conditions investigated we observe a correlatio n between electron pressure profiles and conductivity profiles, sugges ting that [p]/p(0) approximate to (j)/j(0), where [] refers to an aver age over the volume or respectively, the cross sectional area of the p lasma. The profiles become broader as the average current density is i ncreased. These 'profile consistency' features are in apparent agreeme nt with theoretical considerations based on minimum energy states of t he plasma or on stationary entropy. Further analysis of the experiment al evidence, together with a model of the current profile consistent w ith neoclassical conductivity in the confinement zone and correspondin g to a safety factor 0.8 less than or equal to q less than or equal to 1 inside the sawtoothing core, however, shows that the observations c an be accounted for by the effects of sawtooth activity.