Research On The Optimized Profile Structure Of The 2D Plasma Configuration Based On The External Driving Current

On the basis of parameters and experimental datas of the J-TEXT device,the dual magnetic fluid equations and Maxwell equations are used as the theoretical framework.The subject group's self-programming is used to solve the Grad-Shafranov equation in the small circle coordinates.The profile distribution of each plasma parameter is ob-tained,and the spatial distribution characteristics of the magnetic field,flow field,and electric field before and after the pole current reversal are explored.It mainly includes the following research contents:(1)In this paper,by establishing a physical model of the Grad-Shafranov equation for the external driving condition,the influence of different driving current amplitude,injection location and distribution width on the spatial parameter distribution(polar magnetic field,polar current,pressure and safety factor profile)of the plasma is studied by using the control variable method.At the same time,comparing the correlation anal-ysis of different driving effects,a set of optimized distribution parameters was found,which can provide reference and basis for the ECRH experiment and operation of the J-TEXT device.(2)The radial magnetic field and the radial flow field will only appear after con-sidering the high-order Fourier terms of the polar magnetic flux(related to the direction angle).Both the magnetic field structure and the flow field structure of the tokamak plasma should be three-dimensional structures.A physical mechanism is proposed by which external momentum injection can make the pole-direction current partially re-verse,leading to the improvement of plasma confinement performance.The pole-direc-tion current reversal leads to an increase in the total pole-direction current,so that the vortex center of each flow field component is shifted,and the vortex center of the mag-netic field tends to shift to the outside.These research works are helpful to understand the evolution characteristics of the magnetic vortex structure,which can be regarded as the embryonic form of the seed magnetic island,driven by external drive.(3)Numerical simulation of the electric field structure produced by the Tokamak plasma discharge shows that the electric field distribution should be a 3D structure;the center positions of the electric dipoles of the first and second order electric fields are both near the extreme position of⁰;the flow field The contribution of can be of the same magnitude as the ion pressure gradient term in a local area.After applying an external drive to reverse the pole-direction current,the extreme positions and equivalent charge positions of the electric fields of each order tend to move toward the plasma core.These results reveal the complexity of core physics and are helpful for understanding the characteristic behavior of×shear flow.(4)How electromagnetic wave makes plasma produce induced current is further studied.A preliminary theoretical analysis of the physical process of radio frequency electromagnetic waves propagating in plasma is carried out.The working principle of plasma heating by high-frequency electromagnetic waves is pointed out.The analytical expressions for the induced current density and Joule heating power of the electron cyclotron wave and ion cyclotron wave are obtained.The propagation characteristics of electron cyclotron waves and ion cyclotron waves of different frequencies in plasma are analyzed.The Joule heating effect in the plasma can be predicted,Providing a the-oretical basis for the various phenomena observed in the electron/ion cyclotron reso-nance heating/current drive experiment.