大气压等离子体炬电子密度的光谱诊断

利用空心针-板放电装置产生了大气压等离子体炬,采用光谱法测量了其内部及表面的电子密度. 向空心针中通入氩气,在大气环境中产生了长度为1cm的等离子体炬.实验分别测量了Hα谱线和ArⅠ(696.54nm)谱线,通过反卷积方法分离出其相应的Stark展宽,并由此计算了电子密度.结果发现,采用Hα谱线和ArⅠ(696.54nm)谱线Stark展宽计算得到的等离子体的电子密度分别为1.0×10¹⁵cm^－3和3.78×10^{15关键词： 等离子体炬 电子密度 气体温度 Stark展宽}

Spectral diagnostics of electron density of plasma torch at atmospheric pressure

An atmospheric pressure plasma torch is generated with a hollowneedle-to-plate dielectric barrier discharge and the electron densities in the inside and at the surface of the plasma torch are measured by optical emission spectroscopy (OES). A plasma torch with 1cm long is generated in atmospheric ambient when argon gas is introduced through the hollwneedle. The Stark broadenings of Hα and ArⅠ(696.54 nm) lines, which are decomposed from the experimental profiles by using deconvolution method, are used to estimate the corresponding electron densities. The electron densities are 1.0×10¹⁵ cm^－3 and 3.78×10¹⁵ cm^－3 corresponding to the Stark broadening of Hα and ArⅠ(696.54 nm) lines, respectively. The electron density calculated from the Stark broadening of Hα is the same as that at the surface of the plasma because Hα line originates from the dissociation and the excitation of H\-2O at the plasma torch surface where argon can meet with atmosphere. While the electron density calculated from the Stark broadening of ArⅠ(696.54 nm)line is the same as that in the insid of plasma.