Diagnosis Of Key Current Density Distribution

In the Tokamak device,the distribution of plasma current density has been played a key role in the study of plasma equilibrium,magnetic fluid stability,and transport characteristics.The feedback of plasma current density has been an important basis for plasma discharge experiments with high performance and long pulse stability.Motionstark effect(MSE)diagnosis based on neutral atom beam injection heating was the main method to determine the internal magnetic field structure and plasma current distribution.In order to obtain the current density information of MSE diagnosis,the detection system of MSE diagnosis signal was designed,and then tested the obtained signal.The following works have been finished in this paper:1.According to the detection requirements of the diagnostic system,this paper has selected the photomultiplier tube with appropriate parameters as the signal detector.Designed a drive circuit that matches the photomultiplier tube.The precise I-V conversion circuit and multistage operational amplifier circuit have constructed by selecting appropriate operational amplifier.The performance simulation and testing of the detection circuit were carried out to obtain diagnostic signals.2.The remoted control system has been designed by single-chip microcomputer technology and wireless communication.Remotely test the gain and bandwidth influence brought by different feedback resistance values in the detection circuit.scaled the gain resistance value through testing.3.After the signal light has been extracted from the complex background light through the phase-locked amplifier device.The subsequent signal processing was carried out.By collecting and analyzing the obtained data,the tilt angle of the obtained magnetic field and the corresponding plasma current density data was obtained by EFIT magnetic balance program are given.when the system working stably,It was verified that the detection system can reach the required bandwidth and gain level of the diagnostic system through circuit testing The inversion results obtained by the MSE diagnosis system are checked with the data of the polarization interferometer diagnosis system,and error analysis is performed.