| For the study of tokamak plasma,confinement is an important issue.In past decades,it is found that the anomalous transport dominates the electron transport.Usually,anomalous transport is related to the fluctuations of plasma density,temperature fluctuation,electric field,magnetic field and so on.To study the anomalous transport,measurement of the fluctuations is necessary.Up to now,the correlation electron cyclotron emission(CECE)diagnostic system is the only tool to obtain the electron temperature fluctuation information.A set of correlated electron cyclotron emission(CECE)diagnostic system has been developed on J-TEXT.It is used to extract the low amplitude electron temperature fluctuations from the thermal noise by correlation analysis.This paper introduces the design of the new CECE system.It make use the radio frequency(RF)unit of the exist electron cyclotron emission(ECE)diagnostic.The 2-18 GHz output signal is sent to the new intermedia frequency(IF)unit,which consists of eight band pass filters,including two fixed frequency filters(8.0GHz and 8.2 GHz),two 6-18 GHz tunable YIG filters,four 4-18 GHz tunable YIG filters.To improve the poloidal resolution,an optic unit is designed for the diagnostic.It focuses the sample plasma to about 1cm.A YIG control unit is also developed for remotely controlling the YIG filters.A 2M digital acquisition system is adopted for the CECE.Some necessary tests have been taken out first.For example,the bandwidth under different center frequencies of YIG.Comparison of the ECE signal and CECE signal proves the CECE is correct.Some preliminaryexperiment results of electron temperature fluctuation are shown at the end of this paper. |
