Research Of Plasma Parameters And Electrostatic Probe Characteristics In Galatea Magnetic Confinement Device

Controlled nuclear fusion is an important way to solve the e nergy problem in the future. The Galate a de vice is different from To kamak whic h de veloped and researched vigorously. The Galate a de vice is one of non- To kamak magnetic confinement de vices whose current c arrying conductors are immersed in plasma. Galatea has small volume, lo w cost, suppression of plasma co nvective instability and other advantages.This thesis analyses the function and o peratio n principle of e ach core component of Galatea de vice. The de vice is divided as different part according to different functions and the function、structure and parameters is cleared. In this thesis, the plasma description metho ds of single particle orbit, particles in cell and magneto-fluid mec hanics are introduced, and the advantages and dis advantages of each metho d and its applic ation conditions are analyze d. The working principle of the Langmuir probe, electric probe and the e xpression of the pro be curre nt in each area and the c alculation of the parameters are studied.According to the mathematical model of plas ma guide, a finite element simulation model based on COMSOL is establis hed, and the distribution characteristics of guide magnetic field is analyzed, and the uniform magnetic field region and the non- uniform magnetic field region are determine d. Based on the theoretical model of plasma in COMSOL, the simulation model of guide plasma is establishe d, and the spatial distribution and time e volution of plas ma parameters are analyzed. The I-t c haracteristic curve of the electric probe is o btained in the guide plas ma, and the effect of the plasma velocity o n the characteristic c urve of the electric probe is studie d. A metho d to impro ve the parameters of magnetic confinement plasma is proposed.The magnetic trap is the core de vice of Galatea, magnetic trap creates s pecial magnetic field to confine t he plasma. The mathematic al and simulation model are establishe d to analyze the magnetic field characteristics of the magnetic trap, and the we ak magnetic field is determine d. The distribution of plasma in the magnetic trap is studie d by the method of MHD and the installatio n location of the Langmuir probe is determine d. Based on the plasma model in COMSOL, the simulatio n mo del of the magnetic trap is establis hed. The distribution characteristics of plasma parameters are analyze d, and the influe nce of plasm a de nsity and electron temperature on the space potential is analyzed. The results s ho w that plas ma density does not affect the space potential and the electron temperature and space potential are line arly de pendent. The I-V characteristic curve of the Langmuir pro be is obtained in the magnetic trap plasma by simulatio n with COMSOL and t he effect of plas ma parameters on the characteristic curve of Langmuir probe is studie d.The Langmuir probe c haracteristic curve is use d as the object to study the filtering process of the electrostatic probe by using the wavelet thres hold de- noising method. An impro ved threshold function is proposed with the characteristics analysis of soft and hard threshold de-noising methods. Based on the characteristics of I- V curve of Langmuir pro be, an impro ve d standard de viation estimating method is introduced to c alculate the wavelet threshold. De-nosing characteristic curve with impro ve d threshold function and threshold, and the simulation results s ho w that, the impro ve d de-noising metho d perform well, the signal-to-noise ratio is impro ve d and the root mean square error is re duced. The de- nosing effectiveness is better than traditio nal threshold method. A well effect is o btaine d to de al the characteristic curve of actual Langmuir probe with impro ved method.