Simulation Study On Two-dimensional Magnetized Dusty Plasmas

In the early1990s, particularly since the observation of crystal of dusty plasmas in the laboratory, the dusty plasmas have been extensively studied by the experiments, simulations and theories. Fields such as the structure of dusty plasmas, the transport of dusty plasmas and the waves of dusty plasmas turn out to be the very interested subjects for researchers. This thesis focuses on the structure and dynamical properties of the two-dimensional magnetized dusty plasmas through the molecular dynamical simulation method. It mainly contains the following studies: the modified screen Coulomb is derived with considering the plasmas gradient. Based on the modified screen Coulomb potential, the dynamical and structural properties of two-dimensional dusty plasmas is investigated. The fundamental process of relaxation is discussed by changing the initial velocity distribution, the components of dusty plasmas system and the interaction of the charged particles as well as the external magnetic field. The ordered structure above the melting point, named as super-heated solid, of the dusty plasmas is roughly studied by using the velocity scaling method in order to heat the dusty plasmas. In addition, this thesis shows the simulation results of temperature gradient mode of reversed field pinch with including the impurity ions, and the gyro-kinetic simulation of impurity mode.On the other hand, the ion temperature gradient (ITG) driven modes in the presence of impurity ions are studied in the toroidal reversed field pinch (RFP) plasmas by solving the gyrokinetic integral eigenmode equation. The detailed numerical studies resemble the effects of impurities in tokamak plasmas. For instance, the impurities enhance the ion temperature gradient-driving if the impurity populations have density gradients which are opposite to that of the electrons. In addition, the impurity mode will appear when the impurity ion effecs are strong enough.The further study of impurity mode in a RFP using the gyrokinetic integral equation reveals that the impurity mode in RFP plasmas is relatively more difficult to be excited than that in tokamak plasmas under similar geometry when density profile is flat, whereas it turns out to be easier when density profile is rather peaked. In addition, the analysis of the typical RFX-mod experiments is performed and the results show that the ITG and impurity driven modes may be linearly unstable in the edge region of the plasmas when the observed radial profiles of the impurity ions are considered. And these modes may make a considerable contribution to the transport in this region.