[en] A numerical solution to the linearized ion Fokker-Planck equation is presented for large ionization-temperature ratio ZT_e/T_i (≥32). By reducing the equation to an eigenvalue problem through the moment approach, the frequencies and damping rates of ion-acoustic waves in ion-collisional plasmas are calculated as well as the specific heat ratios. Comparing the results with those calculated by Tracy et al. [Phys. Fluids, B5(1993) 1430] shows that the method is accurate enough in large ZT_e/T_i plasmas

[en] Three routes to chaos in a DC discharge plasma under different initial conditions are reported. It is shown that these chaotic phenomena come from the self-oscillation of plasma and the plasma sheaths have contribution to this instability especially in negative space potential

[en] Frequencies and damping rate of ion-acoustic waves in the presence of electron-ion collisions are computed by reducing the linearized electron Fokker-Planck equation and cold-ion fluid equations to an eigenvalue equation via moment expansion of the perturbation of electron distribution function. As electrons becomes less collisional, a great number of Sonine modes are needed for convergence to a desired accuracy in the calculation, which may be ascribed to the neglected electron-electron collisions

[en] Core and edge turbulences were measured by Langmuir probe arrays in the KT-5C tokamak plasma. The radial wavenumber spectra show a quasimode like structure which results in a net radial outward propagation of the turbulent fluctuations. The measured fluctuation levels and wave action fluxes are in good agreement with model predictions by Mattor et al., suggesting that drift wave propagation could be a source of edge turbulence

[en] Experiment results of tristable phenomena in argon gas discharged plasma are briefly reported in this paper. The sudden jumps and hysteresis are phenomenologically analyzed by the catastrophe theory. The intutive physical picture of these phenomena is given by analyzing the states in a potential well

[en] The properties of ion-acoustic soliton such as its excitation, spatial evolution and Mach number are studied on a stable plasma device. The results show that the effect of plasma diffusion on soliton's behaviour should be taken into account under the experimental conditions

[en] A carbon dioxide laser Thomson scattering system has been installed on the HT-6M tokamak. This system is briefly described here. It has been used to investigate turbulent density fluctuations with peak amplitudes between 100 kHZ and 400 kHZ in ohmically heated and in ion-cyclotron-heated plasmas. It was found that ion-cyclotron heating affects the fluctuation level and the spectral distribution significantly. 9 refs, 4 figs

[en] An ion electrostatic probe (Katsumata probe) has been built on the KT-5C tokamak for the measurement of the ion temperature and its fluctuations. The profile of the ion temperatures and its fluctuations in KT-5C were measured from near the core to the edge region (5.5 cm < r < 11 cm) for the first time with the ion electrostatic probe. The experimental results indicate that the gradient of the ion temperature is smaller than that of the electron temperature, and the ion temperature is higher than electron temperature in the edge region, suggesting that there exist interactions between the plasma and the wall. The relative temperature fluctuation of ion T-tilde_i/T_i is roughly equal to that of electron T-tilde_e/T_e and their amplitudes are about half of the electron density fluctuation n-tilde_e/n_e

[en] The physical relationship between naturally occurring large scale (m=2) Mirnov oscillations and small scale turbulence in the Texas Experimental Tokamak (TEXT) is described. Dependences on plasma profiles (e.g density and potential), which are strongly perturbed in the vicinity of the magnetic islands, are unfolded. Theoretical expectations for tearing modes and electron drift waves are compared with the characteristics of the measured mode amplitudes and frequency spectra. The dispersion relation for the turbulent density fluctuations, which propagate in the electron diamagnetic drift direction, is observed to be consistent with that of electron drift wave theory when a Doppler shift due to E-vector x B-vector plasma rotation is included. The fluctuation magnitude is found to correlate with the electron density scale length in a manner following mixing length estimates. (author). 49 refs, 10 figs

[en] In this paper, the research results of the relations between the excitation stage of linear ion Bernstein wave (IBW) and the edge ion density fluctuation, the discharge parameters of tokamak and the antenna position in KT-5B tokamak are presented. The experiments show that large edge ion density fluctuation will make it difficult to excite IBW, the ranges of discharge parameters for optimally exciting IBW are consistent with those for normal operation of KT-5B tokamak. It is find that for the toroidal current antenna used by the authors, there may exist two ways of excitaion, i.e. direct excitation and excitation through the electrostatic mode conversion process