| During tokamak operation,limiting the heat load and electromagnetic load deposition on the first wall of the high-temperature plasma cracking is an important research content for exploring advanced tokamak operation.Different from Tokamak,the anti-field hoop shrinkage shape has a large-current plasma operation but can effectively avoid the advantages of large plasma breakage.Keda Torus experiment(KTX)is a new reversed field pinch magnetic confinement fusion device.The work of this dissertation centered on the three-dimensional magnetic probe system in the electromagnetic measurement and diagnosis system of KTX device,completed the de-crosstalk work in all directions after the platform calibration and installation of the system,ensured the measurement accuracy of the three-dimensional magnetic probe system,and observed the accuracy of the system.The significant displacement of the plasma and its small cracking phenomenon are investigated.First,this paper introduces the design of the three-dimensional magnetic probe system in KTX and the platform calibration of the effective area(NS value)of the magnetic probe.We use the secondary calibration method to place the standard probe and the probe to be calibrated in a uniform magnetic field in a tightly wound long straight solenoid.The ratio of the voltage signal acquired is used to derive the effective area and frequency response of the probe to be calibrated.This section gives the effective area of all three-dimensional magnetic probes that are subsequently used on the KTX device.Second,channel screening and anisotropic crosstalk calibration were performed on the installed three-dimensional magnetic probe.After counting a large amount of existing magnetic probe data,the channel with abnormally unreliable signals is eliminated.In addition,the construction of a fixed field model is compared with a theoretical design model to de-crosstalk the magnetic probe.Firstly,a single vertical field configuration is used to give the hoop crosstalk coefficient of a three-dimensional magnetic probe,and secondly,a single-equilibrium field and single-ohmic field coil discharge of a fixed current is used to give an extremely effective area component of an external three-dimensional magnetic probe.Further,the radial crosstalk coefficient is given by the NS value of the magnetic probe obtained from the mesa test.Finally,the oscillating decay of the ohmic field at the end of the eddy current attenuation gives a crosstalk coefficient of the internal magnetic probe.This part determines the installation angle of the magnetic probe after installation,ie,the actual effective area in each direction,and guarantees the accuracy and reliability of the experimental data.Finally,statistical and modeling studies were performed on the significant displacements of the plasma observed in the KTX experiment and the small fractures it caused.The main feature of the KTX medium-sized cracking phenomenon is the slow outward shift of the plasma current center of gravity prior to rupture.After a small crack,the plasma current center of gravity rapidly moves backward in a hundred microseconds,re-establishing a stable configuration.At the same time,the small plasma rupture is accompanied by the disturbance of the boundary magnetic field with m=l,the stable turbulence on the shell,and the enhancement of the hydrogen-a spectrum and soft X-ray radiation.Based on the analysis and statistics of the KTX small fracture experimental data,the linear relationship between the current center-of-gravity disturbance displacement and the plasma current center-of-gravity displacement is obtained.This paper also establishes a phenomenological circuit model for plasma current distribution and stable shell eddy currents,and draws a conclusion consistent with the experiment.It is determined that the rapidly changing eddy current on the stable shell is an important factor for re-achieving equilibrium after small plasma rupture.Further improvement and improvement of discharge parameters laid a certain foundation... |
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