[en] Soft X-ray diagnosis is an important method in the research of tokamak plasma instability. In this paper, we give the result of soft X-ray measurement in CT-6B tokamak by using Au(Si) surface barrier detector array, and present the spatial distributions of soft X-ray emission for various plasma instability in our device

[en] The hard X-ray emissions from different chords of plasma column and at the limiter have been detected by a detector array on CT-6B tokamak. The experimental results show that the hard X-ray emission is correlative with MHD activity in the plasma. The measured signals are in the same phase as that of soft X-ray from the outer region near q = I resonant surface when sawtooth oscillation occurs, indicating that the most part of runaway electrons is generated in the region

[en] A 9000 series multi-channel instantaneous recorder is described and the software packet developed is introduced

[en] The inward propagation equation of heat wave driven by a weak alternating modulation of the toroidal plasma current in a tokamak plasma has been exactly solved. Based on this solution, an active method to determine the electron thermal conduction in a tokamak plasma has been proposed. The thermal conductivity is calculated as a function of minor radius from the soft X-ray data obtained in experiments on the CT-6B Tokamak. The results indicate the anomalous feature of the electron thermal conduction

[en] A positive limiter biasing on the CT-6B tokamak resulted in a slight increase of edge density and an obvious drop of electron temperature, which is in the temperature range where the rate coefficients for ionization processes are strongly temperature dependent. Concomitantly, edge fluctuations are enhanced, suggesting that the presence of neutral particles may play an important role in modifying edge turbulence

[en] A method to determine the scaling law of the electron thermal conductivity with modulating heat pulses is proposed. Relation between temperature phase lag and parameters is established, from which the electron thermal conductivity in center region of CT-6B tokamak is determined

[en] Langmuir probes and a Mach probe were used for measuring edge fluctuations and parallel plasma flow, respectively, on the CT-6B tokamak. A maximum radial gradient in parallel flow was observed to be located roughly at the maximum E_r shear layer (or, namely, the poloidal velocity shear layer). E_r shear is found to be very possibly consistent with a regulating effect on edge turbulence features. Non-linear analysis indicates that non-linear phase coupling in turbulence may be influenced by E_r shear, or that there exist coherent structures induced by strong E_r shear, and the phase coupling processes show an intermittent character. The results provide some new observations for a better understanding of the basic mechanisms of edge turbulence. (author)

[en] An electron cyclotron resonance heating experiment has been performed by using a gyrotron system for the fundamental and second harmonic resonance heating on CT-6B tokamak. Obvious changes are observed in soft X-ray radiations, electron cyclotron emission, displacement of plasma column, impurity line radiations, and bremsstrahlung radiation when heating pulse is injected, indicating an increase of the plasma electron temperature

[en] Experimental measurements of electron thermal condouctivity coefficient on the CT-6B device are reported here. With the help of MHD internal disruption, which specifies the temperature sawtooth perturbation, and analysing the amplitudes, cycles and phases of the perturbation signals of soft X-ray detectors, the average electron thermal coefficients in different radiuses have been calculated. Experiment results are an order of magnitude larger than that predicted by neoclassical theory, showing that electron heat conductivity in the CT-6B plasma is an anomalous one. It is shown that MHD internal disruption can make the energy transport increases obviously. Electron heat conductivity increases with the amplitude of MHD perturbation

[en] Plasma transport is one of the basic topics in the research of confined fusion plasma physics. Fusion plasma parameters such as electron temperature, plasma density, and the energy confinement time, are seriously limited by anomalous transport. It is of great interest to compare measured and theoretically predicted transport properties. A direct measurement on electron thermal conductivity through the use of internal disruption on our CT-6B tokamak device is discussed here. 8 figs