Design And Construction Works On Diagnostic Neutral Beam Injector And Charge Exchange Recombination Spectroscopy For J-TEXT Tokamak

Tokamak is one of the best ways towards peaceful utilization of fusion energy. Tokamak plasma rotation is a hot research issue for its relations with confinement and transport. Rotation diagnostics are well developed on most major machines in operation worldwide and the charge exchange recombination spectroscopy (CXRS) is considered as the most effective one.J-TEXT lab devotes to constructing CXRS system performing with diagnostic neutral beam injection (DNBI) to assist plasma confinement and transport study. The construction is a bold innovation and practice on behalf of our lab’s plasma diagnostic strength. The design and construction work of DNBI-CXRS tandem is the main theme of this dissertation.The DNBI of TEXT tokamak served several machines and finally rejoined its original partner at J-TEXT lab. We carry out reconstruction and upgrade works emphasizing on beam modulation and beam diagnostics on the DNBI to meet the requirements of J-TEXT tokamak research topics. The implementary strategy of J-TEXT DNBI construction work, which involves the supporting systems such as power supply, gas supply, cooling system and vacuum system, is elaborately developed based on the mainstream injector technology. The high voltage power supply of ion source adopts pulsed step modulation (PSM) technology and the350kW HVPS ensures50kV/6A extraction capacity for the ion source. Beam injection can be modulated with0.5duty cycle to serve CXRS by HVPS control setting. The HVPS has a switch on time about10ms and10μs protection time in case of short circuit. A Doppler shift spectroscopy is developed on the EAST NBI testbed and the main configuration is adopted by J-TEXT. Collecting optics include a50mm commercial lens and multi-channel fibers. Ha lines from different ports on the injector are fitted using multi-Gaussian function and recorded by a0.5m Czerny-Turner spectrometer. A spectroscopy analysis program derives the beam parameters such as energy fraction and beam divergence using beam-gas emission model and1/e line broadening. The calculated results are ready to use between shots for CXRS analysis. The expected J-TEXT CXRS measurement results are provided by a modified spectra simulation program providing plasma, beam and instruments parameters. Design work of a less than1cm special resolution whole radial space covered toroidal CXRS optical system is based on the simulation results. A Czerny-Tuner spectrometer using EMCCD is installed with0.34nm/mm linear dispersion for CXRS use. SNR analysis of the toroidal CXRS system shows a degenerate radial performance inward no worse than80. The construction is quite promising with5km/s、50eV measurement resolutions.