- Hl 2 A Device In The Number Of Effective Charge Spectral Diagnosis Research

Accurate value of the effective ionic charge Zeff is of key importance in a tokamak reactor, since the value of Zeff is related to bremsstrahlung radiation losses, loop voltage, neutron yield, fusion power, etc. The measurement of Zeff is bound up with the accurate measurement of related plasma parameters. Two tasks of this paper are based on the precise parameter values measured by the discharge experiments about visible bremsstrahlung diagnostic in the spectral group on HL-2A tokamak in the Southwestern Institute of Physics. Studying Zeff and its profiles in different discharge configurations and the influences of different heating methods on ZeffThis paper has main introduced the multi-channel visible bremsstrahlung system and the charge exchange recombination spectrum (CXRS) diagnostic system in the HL-2A tokamak. It has expounded spectral diagnostic principle of Zeff and data processing algorithm. Using Matlab to dispose and analyse raw data that were measured by above diagnostic systems. Different profiles of effective ionic charge were obtained based on comparative analysis of different discharge configurations and effective ionic charge in the divertor was50%smaller than that in the limiter. Statistical analysis of the effective discharge of the experiment in spring2010shows 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 (ECRH), while the two heating methods worked simultaneously, the neutral beam injection (NBI) heating could suppress the increase in effective ionic charge. In order to obtain more accurate Zeff, comparing measured bremsstrahlung emissivity with CXRS and based on the background spectrum of CXRS Zeff will be calculated. Only preliminary results were acquired because of the limit of instruments and experiment condition.