A zero-dimensional model is used for studying the behavior of main particle species in atmosphere plasmas with different ionization degrees. The electron lifetimes are obtained for different initial density in an afterglow plasma, and the temporal evolutions of the main charged and neutral species are presented. The results show that the electron number density decays fast, and the lifetimes decrease with ionization degree increasing. Some important neutral species such as O, N, O3 and NO are also analyzed with ionization degree increasing.

A one-dimensional model is used to investigate the reaction-diffusion process of air plasma with a plasma source by numerical simulation in low pressure open atmospheric environment. The spatial evolutions of main charged species’ densities in the chemical reaction, drift and diffusion processes are obtained for a given plasma flow. The results of numerical simulation are combined with an approximate analytical formula to estimate the necessary plasma flow for electron density when a stable state is formed, with which the necessary power of the plasma source also can be estimated.

The electron density fluctuations of CT-6B Tokamak plasma have been studied in detail through the observation of Hα emission intensity by multichannel optical diagnostics. Their various behavior, such as power spectrum, fluctuation level and correlation,have been measured. The experimental results show that some characteristics of density fluctuations are founded in CT-6B Tokamak plasma: the density fluctuation level is about 10%-90% in the radial range r=4-10cm; the point in the range draws, nearer to the edge of plasma the level lecomes higher. A broadband power spectrum is observed at observed points along the plasma radius. There exists a local correlation structure with short correlation time, about 0.2-0.5ms, and short correlation distance , about 0.5-1cm,in the edge of plasma.

The preliminary experimental results o f ac plasma discharges in the CT-6B tokamak.have been achieved by an active plasma current feedback system and the keys to a smooth transition through current zero and some phenomena related to the current reversal phase are also presented.

The four hexagonal grid state patterns and a variety of non-grid states are obtained by changing the values of intensity ratio between two Turing modes in the two-layer coupled Lengel-Epstein model system. Results of numerical investigation show that those grid states in reaction diffusion are interleaving structures of three sets of different sublattices, which result from the interaction of both the wave number ratio and intensity ratio between Turing modes in the two subsystems; and the specific expressions of three-wave resonance in physical space are governed by the mode intensity ratio. Furthermore, the value of intensity ratio between the two Turing modes in the grid state patterns is greater than that of non-grid state structures, and the type of pattern selected by the system changes from complex to simple pattern with the increase of mode intensity ratio. Finally, it is found that these four hexagonal grid states correspond to different number pair (a, b) having different stability, and the grid state with the number pair (3, 2) is the most stable structure.