Study On The Correlation Between Electron Cyclotron Resonance Heating And Poloidal Magnetic Field And Electron Temperature

In order to study the physical phenomena under ECRH and extend the discharge parameter range,the ECRH system was installed in the J-TEXT device and the relevant experimental research was carried out.Previous studies have found that magnetic field plays a key role in the power deposition location of ECRH,and the power deposition location affects the heating efficiency,which is reflected in the evolution of electron temperature.During the discharge of tokamak plasma,impurities will inevitably exist in the plasma.The medium and high Z impurities have great diluteness and radiation energy loss,and the ionizing radiation of impurities is closely related to the electron temperature.In tokamak devices,the pulse height analyzer(PHA)is usually used to measure the energy spectrum of soft X-ray radiation,thereby obtaining some important plasma information,such as electronic temperature,the content and concentration of heavy metal impurities,and the effective charge number Zeff.Considering that the J-TEXT device is currently unable to measure the intensity distribution of the polar magnetic field during the experiment,this paper simulates the effect of the polar magnetic field on the efficiency of O-SX mode conversion under electron cyclotron heating by using the full-wave method based on the cold plasma plate model.The study found that when Ny=0,the existence of the polar magnetic field would lead to the existence of the vanishing region,so the mode conversion efficiency could not reach 100%.Under the condition of setting Nz,the efficiency of mode conversion will decrease rapidly with the increase of the strength of polar magnetic field.When the mode conversion efficiency is the highest,the value of Nz will increase with the increase of the polar magnetic field.Secondly,the introduction of the XR-100 FAST SDD detector on the J-TEXT tokamak device and the upgrade of the soft X-ray energy spectrum diagnostic system are introduced.By studying the experimental results under different discharge parameters,the optimal parameter interval of soft X-ray spectrum acquisition on J-TEXT device was obtained.Finally,the physical phenomenon of electron cyclotron heating on the J-TEXT device was studied,and the obvious double-temperature phenomenon was observed in the low-density experiment.By studying the resonant disturbance field and the change of electron temperature in the plasma core under the resonance effect of ECRH,it was found that the constraint of ECRH on the plasma was significantly improved.Finally,the effects of electron cyclotron input power,electron density and longitudinal field on heating efficiency are analyzed.