The electron cyclotron resonance heating experiments on HL-1 tokamak

The electron cyclotron resonance heating (ECRH) experiments on HL-1 tokamak with 300 kW of power generated by a gyrotron are described. With ECE diagnostics, a 30% increase of electron temperature has been obtained. The following phenomena have been observed with various diagnostics during ECRH: increase of radiation intensity of soft x-ray; amplitude change and period elongation of sawtooth oscillation; MHD instability suppression; increase of Hα spectral line intensity and ionized impurity radiation from edge plasma; increase of the temperature and density of edge plasma. Although the total plasma energy content increases, the energy confinement time is decreased. Initial results of low voltage start-up experiments have also been obtained.