进行大气压氦气介质阻挡放电,通过测量放电起始电压和发射光谱,研究本底空气压强BAP在0.8～1000Pa时放电中彭宁电离作用的变化规律.结果发现:BAP＜190Pa时,放电起始电压显著降低,N_2~+第一负区391.4nm谱线强度随BAP增大而增大;BAP＞190Pa时,放电起始电压显著线性增大,391.4nm谱线强度随BAP增大而逐渐下降,最终几乎趋于零.He原子的各谱线强度随BAP增大而逐渐递减.探讨其物理过程为:放电起始电压的结果和发射光谱的结果均指出彭宁电离作用随BAP改变而变化;He原子各谱线强度变化是由于淬灭造成的.%The change law of Penning ionization in atmospheric helium dielectric barrier discharges (DBDs) with air impurity was investigated. Discharge inception voltage and emission spectra were measured under different background air pressures (BAPs) changing from 0.8Pa to 1000Pa. Results of these two kinds of methods showed that in a range of BAP from 0.8Pa to 190Pa, discharge inception voltage decreased obviously and the 391.4nm line intensity increased with the BAP. When BAP arrives at more than l90Pa, discharge inception voltage increased linearly obviously and 391.4nm line intensity gradually dropped to lower value with the BAP, even a zero value at last. Emission spectra of helium decreased with the BAP. Physical processes analysis indicated that the results from both discharge inception voltage and emission spectra illustrated that Penning ionization due to helium metastables and N_2 changed with the BAP, and the changes of all emission spectra intensities of helium are due to the quenching caused by N_2.
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