Analysis Of Plasma Equilibrium Flow Filed And Its Effects

Nuclear fusion is the most reliable approach for human beings to obtain energy in the future, yet tokamak magnetic confinement device is one of the most likely approaches to realize the controllability of nuclear fusion. By adopting the ideal magnetohydrodynamic(MHD) model, this thesis conducts a study of the equilibrium and rotation of tokamak plasmas through the using of numerical simulation based on the basic parameters of J-TEXT device. The thesis mainly covers the following four parts:(1)Through deduction and solving the Grad-shafranov equilibrium equation under the small toroidal coordinate, such equilibrium parameters as plasma equilibrium configuration and magnetic field structure under the small toroidal coordinate which reaches easier comparison with the experimental data based on J-TEXT tokamak are obtained, which basically match the results of laboratory measurements.(2)By using the fluid's incompressibility and the magnetic freezing effect of the ideal MHD model, self-consistent flow field physical model is deducted. The rotational speed of core obtained through experimental measurement is used to determine the form and parameters of stream function, thus the 3D self-consistent flow field under the small toroidal coordinate is solved. Then, the self-consistent flow field's influence to balance is studied through equilibrium equation, which provides certain theoretic foundation for the research of flow field.(3)Starting from toroidal momentum equilibrium equation and meanwhile making equilibrium flow equivalent to internal momentum source, a physical model used for the calculation of rotational speed driven by lower hybrid waves when calculating equilibrium flow is built and simulated, thereby successfully explaining the velocity shear and reversal phenomenon observed by experiment. It will provide certain reference for lower hybrid injection experiment conducted under J-TEXT.(4)Various equilibrium is solved concerning the tokamak plasma, a highly nonlinear system. Such equilibrium parameters as paramagnetic, converse magnetic, paramagnetic-converse magnetic are obtained and compared. The thesis finds out that poloidal beta could be increased effectively as long as the poloidal current reverses(the marginal area takes the form of converse) driven by external device, which furthermore offers reference for how to improve the confinement property and stability of the J-TEXT device in future.