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该文采用2D对称流体力学模型,研究N2含量对大气压He等离子体射流的管外放电结构和粒子组分的影响.工作气体为He和He-N2混合气体,混合比为x(He)/x(N2)=99.85/0.15,x(He)/x(N2)=99.7 /0.3和x(He)/x(N2)=99/1.工作气体中混合N2增强等离子体放电,并且x(He)/x(N2)=99.7/0.3混合气体中的等离子体放电最强.1％ N2含量内潘宁电离的促进作用强于电子激发N2分子反应的削弱作用,但是He混合1％N2对应的电子激发反应消耗的能量也起很大作用.混合N2能够加速等离子体子弹从环形结构向实心结构的转变.N2含量对介质管外等离子体射流中的离子组成有很大影响:纯He等离子射流中He2+密度最大;工作气体为x(He)/x(N2)=99.85/0.15和x(He)/x(N2)=99.7 /0.3混合气体时,N2+和N4+密度明显高于He+和He2+;工作气体为x(He)/x(N2)=99/1混合气体时,N4+完全主导正离子电荷.“,”Using a 2D axisymmetric fluid model the effect of the level of N2 admixture on the discharge structures and the ionic compositions outside the dielectric tube of a He atmospheric pressure plasma jet has been studied.The working gas is He,x(He)/x(N2)=99.85/0.15,x(He)/x(N2)=99.7/0.3,and x(He)/x(N2)=99/1 mixtures.The N2 admixture in the working gas enhances the discharge for plasma jets,and the discharge for the plasma jet in He with 0.3％ N2 admixture is the strongest.The role of the Penning ionization reactions is considered to be prior to the electron excitation reactions of N2 molecules within 1％ N2.However,the energy consumed by the excitation reactions of N2 molecules is also important for the plasma jet in He with 1％ N2 admixture.The N2 admixture accelerates the transition from the annular structure to the solid shape of the plasma bullet outside the dielectric tube.The ionic compositions of plasma jets outside the dielectric tube are strongly dependent on the N2 concentration.He2+ determines the positive charge for the plasma jet in He,N2+ and N4+ both play an important role for the plasma jets in x(He)/x(N2)=99.85/0.15 and in x(He)/x(N2)=99.7/0.3 mixtures,and N4+ completely dominates the positive charge for the plasma jet in x(He)/x(N2)=99/1 mixtures.