Electron Cyclotron Current Drive And Current Distribution Control In Tokamak

In order to make okamak operate steadily with high-performance, non-inductive current drive method must be used to generate current of plasma, and control the distribution of driving current. In the electron cyclotron current drive, due to high frequency of electron cyclotron waves and narrow width of the drive current level , as well as preferable ability of propagation and localized nature of wave energy deposition,it would be a very attractive method for driving using cyclotron waves to drive current of plasma.Firstly, using the geometrical optics approximation and the cold plasma dispersion relation, we track electron cyclotron wave propagation in plasma and numerically solve the wave equation, which can determine the wave propagation properties in the plasma. The expressions of collision flux, electric field flux and wave induced flux in the momentum coordinates are deduced in consideration of the relativistic effect of high velocity particles for the case of electron cyclotron current drive (ECCD). Also the form of 2-D Fokker-Planck equation which can be solved by using numerical method is obtained. Using the 2-D Fokker-Planck equation and wave equation, we numerically simulated electron cyclotron current drive and wave power deposition. We obtaind the normalized radius of the drive current density and power deposition distribution, wave power deposition and driven current density distribution of different temperature, and current density distribution of different wave power input for EAST. Also we have analysed the effect of the different electron cyclotron wave on driven current and wave power deposition.At last, we discussed the formation of hollow bootstrap current distribution in the condition of the advanced tokamak operation mode. We also studied that the electron cyclotron wave can be used to drive plasma current and control plasma current profile distribution. The relationship of the driving current distribution and incident wave spectrum and incident angle is also discussed. In the hollow center of the plasma, the incident wave spectrum and the location of wave emission can control the current distribution. The appropriate electron cyclotron emission angle and wave power spectrum can achieve the purpose of controlling current in the center plasma.