The ion temperature evolution on TCA during Alfven wave heating and in non stationary ohmic conditions

High power Alfven Wave Heating has been applied to the TCA tokamak and results in an electron and ion temperature increase, together with a plasma density rise. The various terms leading to an ion temperature increase are investigated to determine whether any of the applied RF energy is absorbed directly by the ions. This is done by a detailed comparison with non stationary ohmic discharges. We conclude that although a large fraction of the ion temperature increase may be assigned to the density increase, there remains a component that is most simply described by a direct ion heating. (author) 18 figs., 10 refs