A New Method For Field-Reversed Configuration Equilibrium Design And Reconstruction

Controlled fusion energy is one of the most promising ways to solve the energy problem of human beings.The inertial confinement fusion(ICF)and magnetic confinement fusion(MCF)have been the focus of controlled fusion research,and great achievements have been made in these fields.However,with the growing complexity of ICF and MCF,and the extra high cost for building experimental devices,the traditional fusion routes still have a long way to go to reach the goal of commercial fusion power generation.ICF is characterized by extremely high plasma density and short plasma confinement time while MCF is a low density and long confinement time approach.Magneto inertial fusion(MIF),with plasma densities and confinement times intermediate between ICF and MCF,is considered a promising alternative approach for commercial and compact fusion reactors,which may significantly reduce the cost of fusion.In MIF,a magnetized plasma target is preheated,then transferred to a compression chamber,where the plasma target is compressed to achieve fusion ignition.Field-reversed configuration(FRC)is a simple axisymmetric compact toroids with high plasma β,which has no central penetration and can be easily transferred axially.Due to these features,FRC are suitable as the target plasma for MIF.After they are formed,FRC plasmas have been observed to achieve stable equilibrium for many Alfven transit times.Understanding the detailed features of the FRC equilibrium is of fundamental importance for the research of FRC instability,transport,and compression processes.The FRC equilibrium is investigated in this dissertation,and the content is summarized as the following:In chapter 1,the background and significance of this dissertation are introduced,including a literature survey of the current status of MIF experiments,and of the characteristics and research status of FRC experiments.In chapter 2,the basic properties of FRC equilibrium are introduced,and a review of the FRC equilibrium research is presented.In chapter 3,a two-parameter Modified Rigid Rotor(MRR)equilibrium model for describing the FRC plasmas is developed.It is shown that the previously most frequently used Rigid Rotor(RR)model is a single-parameter model,which lacks the flexibility to describe experimentally observed narrow scrape off layer(SOL)thickness and hollow current density profile.The new MRR model has sufficient flexibility and can be used to fit experimental measurements well.In addition,a new analytical method for solving the free parameters of the equilibrium model is developed,and it is shown that 1D equilibrium of FRC is determined by two physical parameters.A database of equilibrium model parameters that can be used for 1D real-time equilibrium reconstruction is generated.In chapter 4,the GSEQ-FRC code,a 2D equilibrium calculation tool,is developed.The new tool improves the efficiency of the equilibrium calculation by setting the values of the maximum vacuum magnetic field and the separatrix radius as scaling factors and perform the calculation in a normalized system.The factors affecting the shape of the FRC separatrix are investigated using the GSEQ-FRC tool,and the relation between the shape of the separatrix and the pressure gradient is shown.In chapter 5,the dynamic formation of FRC is investigated using the self-developed MCT code,which is a magnetohydrodynamics(MHD)code.The two-fluid 2D FRC equilibrium is calculated using the N-fluid equilibrium code,and the properties of two-fluid equilibrium is studied.In chapter 6,the conclusions of this dissertation are summarized,and the outlook to the future work is given.