On Three Dimensional Distribution Of Particles And Temperature In Beam Transportation Space And Vacuum System Optimization For EAST-NBI

Neutral Beam Injector (NBI) is a device for Experimental AdvancedSuperconducting Tokomak (EAST) plasma heating and plasma current driving bygenerating high energy neutral particle. In the process of high energy neutral particletransmission, the state of vacuum environment in Transport space for the generationand transmission process of beam is very important influence. The national greatscience engineering device of EAST-NBI as the research object, to study threedimensional distribution of particles,temperature and pressure in beam transportationspace, explore the physical behavior characteristics of particles, optimize the design ofthe vacuum system,it has very important significance for beam generation andtransmission efficiency This paper research the structure and working principle of EAST-NBI device, Thegeneration of plasma, derivation of the high energy ion beam and neutralizationprocess are analyzed. Based on EAST-NBI device, rarefied gas dynamics analyzesphysics behavior and characteristics of beam transport space gas particle. This theoryestablishes the physics model of EAST-NBI Beam transport space. Adopting DSMCmethod to simulate and analysis particle, Particle density, pressure and Velocityvector distribution of EAST-NBI ion source and neutralizer. Provide theoretical basisfor Improve the ionization efficiency, gas utilization efficiency and proton ratio of theion source. To help obtain the best target thickness and Improve the efficiency ofneutralization. Adopting Monte Carlo method to simulate and analysis particle,Particle density, temperature and pressure distribution of the EAST-NBI vacuumUnder different working conditions. And also To simulate and analysis Position beameffect and Angular distribution at Important parts of the vacuum chamber. Providetheoretical guidance for optimal design of the EAST-NBI vacuum system and reducethe ionization loss again. To research and analysis the Structure of EAST-NBI,Adopting Monte Carlo method to conduct and simulate Molecular transmissioncoefficient of the front cryopump chevrom radiation baffle. To research and analysisparticle distribution of the rear cryopump radiation baffle. Optimizing the compositionof the gas damper and location of the vacuum chamber, optimize the structure of theradiation baffle. Help to improve the differential extraction effect.This article researchresults help to beam generation and transmission efficiency and Provide the basis forfurther optimizing the system performance,has engineering practical value.