Experimental Study On The Plasma Equilibrium Profile Distribution Of J-TEXT Tokamak

In the tokamak plasma discharge experiment,the electron density and current density of the plasma are two very important basic parameters.The far-infrared laser POLARIS system on the J-TEXT can measure these two quantities simultaneously.The system has excellent performance at the initial stage of completion,which provides a good diagnostic basis for the operation of J-TEXT Tokamak and the development of physical experiments.After years of operation,the signal quality of the system has declined in recent years.Based on the importance of density and current density in physical experiments,we have carried out the signal optimization work of the J-TEXT POLARIS.At the same time,due to the needs of the density limit subject research and considering the significant influence of the boundary plasma behavior on the density limit,we have upgraded the J-TEXT POLARIS.On the other hand,based on the good profile observation performance of the multi-channel POLARIS,we have studied the equilibrium profile distribution of the J-TEXT plasma under a variety of discharge experimental conditions.Therefore,the work of this paper mainly includes the signal optimization of the J-TEXT POLARIS,the upgrade of the POLARIS boundary measurement and the observation of the plasma balance profile.The thesis first introduces the J-TEXT POLARIS system,which mainly includes the collinear error analysis of the system and the improvement of the collinear adjustment optical path,the investigation and analysis of Faraday angle signal interference,the optimization of Faraday angle measurement,and the handling of the flip error of the stripe jump during density measurement.The second part of the thesis mainly describes the upgrade of the J-TEXT POLARIS.First,it analyzes the light path of the J-TEXT light collection end,Construct a new detector array on a plane perpendicular to the diagnostic window of the POLARIS,and combines the POLARIS grid.The optical signal is more fully utilized,and the POLARIS system on the J-TEXT device is upgraded to improve the spatial resolution of edge plasma measurement,so that the spatial resolution of the low-field side boundary reaches 1.5cm,and gives the string integral density signal and Faraday angle signal,as well as the plasma density profile and current profile after signal processing are provided,and the system profile measurement results are compared and analyzed.The third part of this article observes and analyzes plasma profiles under various experimental conditions.First,the evolution characteristics of the plasma equilibrium profile during the density limit experiment are described,which mainly include the density profile,current density and electron temperature profile.In addition,this paper preliminarily studies the influence of electron cyclotron resonance heating(ECRH)on the plasma profile,and the influence of magnetic fluid instability on the plasma electron density and current density profile.Finally,the plasma profile under the limiter and divertor configuration is compared and analyzed.