INVESTIGATION OF T-11M TOKAMAK PLASMA ION-CYCLOTRON HEATING

A novel method of discharge chamber wall boronization was used in the T-11M tokamak. The method is based on carboborane (B10C2H12) decomposi tion in a helium discharge. The boronization facilitated an increase o f the ion-cyclotron heating (ICH) input power from 100 to 200 kW and t he heating efficiency from 1 to 3.5 eV/(kW cm(3) x 10(13)) in discharg es with plasma density ($) over bar n(e) = 3.5 x 10(13) cm(-3) and n(H )/n(D) = 7 - 10% A considerable increase (about 25%) occurred in the p lasma column electron density during the ICH. This increase seemed to be due to improved particle confinement rather than to recycling enhan cement. The energy confinement time was rising during the heating. Thi s rise could be attributed to both the plasma density buildup and part icle confinement improvement. The observed deuterium temperature dynam ics at the tokamak axis is adequately described by the ICH quasi-linea r theory for a hydrogen-doped plasma.