`Profile consistency' features in shaped sawtoothing ohmic TCV plasmas

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Abstract
A large variety of plasma conditions has been created in TCV (Tokamak à Configuration Variable, 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 correlation between electron pressure profiles and conductivity profiles, suggesting that , where refers to an average over the volume or respectively, the cross sectional area of the plasma. The profiles become broader as the average current density is increased. These `profile consistency' features are in apparent agreement with theoretical considerations based on minimum energy states of the plasma or on stationary entropy. Further analysis of the experimental evidence, together with a model of the current profile consistent with neoclassical conductivity in the confinement zone and corresponding to a safety factor inside the sawtoothing core, however, shows that the observations can be accounted for by the effects of sawtooth activity.