Analysis And Design Of Physical Parameters Of China Astro-Torus No.1 Dipole Field Magnetic Confinement Device And Levitated Magnet Scheme

Fusion energy is the fundamental way to solve the shortage of human energy and environment.Since Hans revealed the source of planetary energy,scientists have never stopped exploring controlled fusion.From mirror to stellarator to tokamak,scientists have been trying to control fusion energy.So far,great progress has been made.Fusion energy has entered the stage of fusion reactor engineering development from experimental physics.As a new approach to explore fusion energy,dipole field magnetic restraint has the advantages of simple structure,no rupture and high specific pressure.China Astro-Torus No.1 is the first magnetic confinement device designed with suspended dipole field coils in China.The confinement configuration draws lessons from the stable configuration of magnetized planets and neutron stars in the universe.The physical parameters of CAT-1 are:plasma density and temperature are 5×1019 m-3 and 500 eV respectively,the radius of vacuum chamber is 4 m,and the magnetic field on the outer surface of superconducting ring is more than or equal to 5 T,reaching the existing domestic HL-2M and EAST tokamak parameters level,that is,medium plasma physical parameters constraint level.The main work of this paper is also focused on the design goal of CAT-1.Through the self-developed dipole field quasilinear plasma transport program,the empirical scaling relationship between the device energy constraint time and the device physical engineering parameters is obtained,which is used to calculate the main engineering and plasma physical parameters of CAT-1.Through the calculation of dipole field magnetic configuration and electromagnetic stress,the preliminary work of superconducting suspension magnet is carried out feasibility analysis of the project.The details are as follows:Firstly,based on hard core Z-pinch,the scaling relationship of energy constraint time τE and average plasma specific pressure(?)is given under the limit of CAT-1 cylinder.The quasilinear transport model is derived from the magnetohydrodynamic equation.The application of quasi linear transport model to calculate under CAT-1 parameters τE=1.1× 10-2 sec and(?)=6×10-3.maximum temperature Tmax=313 eV,maximum plasma density nmax=0.4 × 1019 m-3。Compared with Bohm transport and classical transport,the quasilinear transport model has obvious effects on the quantity constraint time τE,the average plasma specific pressure β and the maximum temperature Tmax.Secondly,the scaling relation calculated by the iterative program shows that the parameters τE,β and Tmax have a significant positive correlation with the device radius Rw and the plasma external boundary temperature Tw.Therefore,the radius of the device can be increased and the divertor design can be improved to increase the plasma temperature.At the same time,it can increase the coil current,increase the maximum plasma density and improve the performance of the device.Thirdly,two kinds of CAT-1 dipole field coils are proposed for the low temperature superconductivity and the high temperature superconductivity.The size radius of the coil in the low temperature superconductor scheme is 0.5 m and 0.25 m respectively,the current carrying capacity of the coil is 5×106 A,the maximum magnetic field strength on the coil surface is 12.7 T,and the maximum stress and strain of the magnet are 7.5×107 Pa and 0.073 mm respectively.The coil size of the high temperature superconductor scheme is the same as that of low temperature superconductivity,the current carrying capacity of the coil is 6.57×106 A,the maximum magnetic field strength on the coil surface is 14.8 T,and the maximum stress and strain of the magnet are 1.03×108 Pa and 0.098 mm respectively.Both schemes meet the design objectives of CAT-1.The main engineering and plasma parameters of CAT-1 are given based on the magnet parameters and calibration formula of the cryogenic superconducting design scheme.In conclusion,based on the general objectives and design requirements of CAT-1,the calibration relationship between the time τE and the average plasma specific pressure β for the critical parameters of the device design is completed.Based on the two feasible schemes of low temperature superconductivity and high temperature superconductivity,the design of CAT-1 dipole field coil is completed.The results and analysis show that the relevant objectives and requirements are met in general.