FIRST RESULTS OF THE 140 GHz, 0.5 MW ECRH EXPERIMENT ON THE FTU TOKAMAK

摘要

The results of an ECRH experiment at 140 GHz, 0.5 MW, 15 ms, on the FTU tokamak are presented. The EC waves, generated by GYCOM, a gyrotron with gaussian output, are transmitted to the plasma with an efficiency of ≈ 93% by a hybrid system comprising both mirrors and corrugated waveguides. The waves, launched as an O-mode at the fundamental EC resonance from the low magnetic field side, are almost totally absorbed by the target plasma in a layer 4-8 cm wide, and cause an electron temperature increase of 0.8-2.5 keV. At electron densities above ≈ 10~(20) m~(-3) the neutron production rate is also strongly enhanced (50-100%), the increase following the start of the ECRH pulse with a delay consistent with the e-i collision frequency. The ECRH power has been modulated to generate heat waves for confinement studies.