Effective Ionic Charge Measurement Using Visible Bremsstrahlung Emission in the HL-2A Tokamak

In the HL-2A device,effective ionic charge was computed from line integrated signal that were measured by the multi-channel visible bremsstrahlung emission system.Different profiles of effective ionic charge were obtained based on comparative analysis of different discharge configurations and effective ionic charge in the divertor was 50% smaller than that in the limiter.Statistical analysis of the effective discharge of the experiment in spring 2010 shows that the inhibitory effect of divertor impurity.Analysis of different plasma heating methods shows a significant increase in effective ionic charge during the electron cyclotron resonance heating,while the two heating methods worked simultaneously,the neutral beam injection heating could suppress the increase in effective ionic charge.