Numerical Simulation Study On Design And Operation Characteristics Of Low Energy Permanent Magnetic EBIT And Ultra Low Energy And High Temperature Superconducting EBIT Electronic Optical System

More than90%of the visible substance in universe are plasmas. The study of plasmas not only enables us to search the secret of the space, but also helps to promte the developments in modern technics, especially to the solution of the urgent demand for new energy sources. The Tokomak device is one of the most effective approach to the quest for controlled fusion. The research of the plasmas inside the tokomak device is of no dout very significant and important.Electron Beam Ion Trap (EBIT) is a small scale accelerator type device which is a good light source and also an important ion source. In an EBIT the electron beam is quasi mono-energetic and the ion density is quite low, these properties makes EBIT a very useful tools for high resolution spectroscopic research and disentanglement studies of atomic processes in plasmas. Shanghai-EBIT, which was established at Fudan University in2005, is one of four Super-EBITs in the world.It is quite useful for core plasmas of Tokomak. But in order to assist studies on edge plasma spectroscopic diagnostics,ultra low energy EBITs which can provide electron beam energy of lower than300eV or even50eV are urgently in need. This is why the low energy EBITs are developed all over the world. The main theme of this thesis is on improvement and brand new design of the electro-optical systems for ultra low energy EBITs. Large amounts of simulations and systematic analysis are made to lower the limitation of electron beam enery and offer guidance for experimental operation.Detailed works are as below:I.The first domestic ultra low energy EBIT, SH-PermEBIT, has been developed which has reached a low energy electron beam energy of around250eV. Through large amounts of program numerical simulations, animprovement on the electro-optical system was made to successfully push the electron beam energy to as low as60eV. A systematic understanding on the properties of experimental operation and electron beam conditions of SH-permEBIT is established. With the guidance of the simulations, Ar and W spectra are successfully obtained at ultra low beam energy. This will laid a great foundation for the study of edge plasmas of Tokomak device.II. On the basis of simulation studies for factors which hinder an EBIT to operate at very low electron energie, combined with the experimental research, magnetic mirror effect, axial, radial, and total kinetic energy distributions were analyzed for all the electron trajectories. Influences from the electron current and electron energy on the energy depression caused by space charge are analyzed. With the consideration of all the factors, disscustions on how to lower the electron beam enery was made.III. The brand new design of electro-optical system for extremely low energy EBIT is developed. Simultion studies and analysis are presented and show that the electron beam energy can reach below50eV. A systematic describtion of the beam conditions on extremely low energy operation is presented. The SH-HtscEBIT which has the break through electro-optical system, has been set up, the experimental operation test is now on going.IV. Several designs of electron guns with new type of cathodes are presented, which are intented to be alternatives for SH-permEBIT and SH-HtscEBIT. We come up a new electromagnetic optimization design method for high temperature magnets.