Development Of Radiation Diagnostic System For HFRC Field-Reversed Configuration Plasma Device

The radiation power of plasma is an important parameter which can provide the information of impurity distribution,energy balance and confinement performance.As a basic diagnostic method for high temperature plasma,radiation diagnostic is mainly used to measure the radiation power during plasma discharge.It is also widely used to study the formation and tilt instability of plasma on field reversed configuration(FRC)device.A high-performance field reversed configuration plasma device(HUST Field Reversed Configuration Device,HFRC)is being designed and built by Huazhong University of Science and Technology.With the aim of providing raw data of radiation and supporting physical experimental research,a radiation diagnostic system including total radiation diagnostic and H? radiation diagnostic should be developed on HFRC.First,the radiation power was evaluated based on the collision radiation model in order to identify the radiation characteristics of HFRC plasma and the radiation energy spectrum at different temperatures was analyzed.The impurity distribution and radiation profile of HFRC plasma is also provided by STRAHL,a one-dimensional impurity transport code,under various scenarios.These works will provide a theoretical basis for the design and performance evaluation of radiation diagnostic.Secondly,a total radiation diagnostic was designed to measure the total radiation power of the plasma.This diagnostic is equipped with a pre-photocurrent amplifier to reduce electromagnetic noise during the transmission of signal.It can achieve a spatial resolution of2.5 cm and a temporal resolution of 500 k Hz with 16 view chords.To solve the problem that the total radiation diagnostic cannot balance the time resolution and measurement accuracy on the existing FRC device,a dual photodiode detector scheme based on AXUV and SXUV was proposed to correct the measurement results of AXUV.In this scheme,the correction coefficient? of the AXUV can be obtained by the difference in the response of the two detectors.And the accuracy of measurement by AXUV can be significantly improved from 50% to about 95%with the effect of ?.It has been verified that the dual photodiode detector scheme performs well under different temperatures,impurities and transport conditions.It can provide a good time resolution and measurement accuracy at the same time.Finally,a H? radiation diagnostic was developed to study the flux of neutral hydrogen and recycling.This diagnostic can provide 35 view chords with a spatial resolution of 1.1 cm,a temporal resolution of 500 k Hz,and a rise time of 0.8 ?s.Based on frequency compensation,the transimpedance amplification scheme was adopted to achieve a high performance in gain and bandwidth.The response under different incident angles was calibrated by a standard brightness source,which can eliminate the influence of incident light angle on the transmittance of the H? filter.And the performance of diagnostic was verified by the offline test.Preliminary experimental data has been obtained on HFRC formation device.