| Nowadays there are two main challenging problems in the field of transient plasma temperature diagnostics:one is the ultra-fast and ultra-high plasma temperature diagnostics in a dynamic launching system in national defence and military, the other is2D/3D distribution of space plasma temperature exsited in various magnetically-confined nuclear fusion reactors. In this thesis, spectroscopy technology based plasma temperature diagnostical methods are proposed, in which means acquiring the intensity of the plasma radiation or demodulating corresponding interferogram which contains the plasma spectral information. The main research work is summarized in the following paragraphs.First of all, for real-time diagnostics of the transient plasma temperature in a dynamic launching system, the property of blackbody radiation law has been studied. To overcome the difficulty of the unknown spectral emission efficiency in this law, several multiple wavelength-based hypothesis models and functions have been introduced as a substitute for this unknown parameter. These models and functions, as well as the target temperature, can be solved by using various curve fitting algorithms including advanced automatic order selection mode and advanced stepwise regression mode, both based on least square method. The simulation results indicated that a comprehensive utilization of all these modes can result in radiation temperature error within1.5%and spectral emission efficiency error of less than0.1.Second, using the results above, a transient multi-spectral pyrometer has been developed which includes an ultra-high spectral resolution reflecting grating and an ultra-fast responding avalanche diodes array as the detector. And a series of accurate calibration experiments using several spectral lamps (Ne and Hg) and a bromine tungsten lamp demonstrated that the system spectral resolution reaches0.4nm and the central wavelength error of each spectrum is constrained within0.55nm. The outfield experiment was carried out and the results showed this pyrometer successfully recorded flame spectrum intensities and temperature results lasting less than10ms. Also, the system temporal resolution can be up to100μs and system error is within2%.Third, in order to recover the2D distribution of the transient plasma’s drifting velocity and ion temperature in a magnetically confined device, the plasma spectrum broadening and central frequency shifting mechanism influenced by both temperature and magnetic field are studied. Several relationships are derived, including the Fourier transform between interferogram coherence and the reconstructed line shape, the function between the fringes’phase shifting and Doppler drifting velocity based on Doppler spectroscopy as well as the function between fringes’coherence decline and ion temperature. Also, according to the static and dynamic test purpose,3different algorithms including the absolute calibration based on a laser,4-step phase-shifting and3-step phase-shifting methods have been proposed.Finally, according to the theory of interference spectrum and results above, a polarization interference imaging spectrometer with the emphasis on the FOV (field of view) compensation technology using a novel Savart splitter has been developed. The Ar II488.Onm laser spectrum, as the calibration source, has been successfully reconstructed by this spectrometer and the result shows the system can reach a spectral resolution of86.8cm-1and an angle of field of view around5.54°as well as a central wavelength error within0.1nm. An outfield experiment was carried out on the magnetic confinement helicon plasma device MAGPIE (Magnetized Plasma Interaction Experiment) and the Doppler drifting velocity and ion temperature of Ar II488.0nm plasma were reconstructed. Furthermore, several other diagnostics have been accomplished under different MAGPIE configuration parameters (RF antenna power, gas pressure and magnetic strength) and corresponding results were in a good agreement with plasma physics theory. |
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