›› 2012, Vol. 32 ›› Issue (3): 72-77.doi: 10.3780/j.issn.1000-758X.2012.03.011

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Effect Analysis of Plasma Density on Ion Beam Extracted by Grid System

 JIA  Yan-Hui1, LI  Zhong-Ming2, ZHANG  Tian-Ping1, LI  Juan2   

  1. (1 Science and Technology on Vacuum & Cryogenic Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000)
    (2 Yiwu Industrial & Commercial College,Yiwu 322000)
  • Received:2011-10-10 Revised:2012-06-25 Online:2012-06-25 Published:2012-06-25

Abstract: Presentanalysesontheionbeamofthegridsystemdonottakeaccounttheplasmadensityindischargerchamber.Ionbeamextractionwassimulatedbytheparticleincell(PIC)method.Theelectricfieldwascalculatedbythefinitedifferentialmethod(FDM),andtheionparticleswereacceleratedbytheleapfrogmethod.WithChinese20-centimeterXeionthruster,theelectricpotentialandionbeamdistributionsinthecenterandbrimapertureofgridsystemwereobtained.Theresultsshowthattheionbeamextractedbythecenteraperturehasbetterfocuspropertyandsmallerdivergenceanglethanthatofthebrimionbeam.However,thesaddlepointpotentialofthecenterapertureis24.8V,higherthanthatofthebrim.Hence,theplasmadensityindischargerchamberhasanimportanteffectontheionbeamextraction,andelectronbackstreamingphenomenatakeplaceonthecenterpositionofgridsystemfirstly.