摘要
对于O2,O2/He,O2/Ar等的气体放电过程,进行了玻尔兹曼方程的计算求解,获得了电子能量分布函数、平均电子能量、能量利用效率等参数。计算结果表明,获得的电子能量分布函数呈现出典型的非麦克斯韦型分布,这说明在较低的电场强度下不宜采用麦克斯韦型分布的电子能量分布函数。在同样的约化场强(E/N)下纯氧放电的平均电子能量最低,加入载气He和Ar后平均电子能量增加。同样氧气含量的O2/He和O2/Ar混合物,其平均电子能量随着约化场强的变化曲线存在一个交叉点,当E/N较小时,O2/Ar的平均电子能量较高,而当E/N较大时O2/He的平均电子能量较高。添加NO气体对击穿场强影响不大,因此在放电气体中引入NO,降低电离能进而降低约化场强E/N并不是提高单重态氧产率的主要因素。当氧气中含有15%的单重态氧O2(a1Δ)时对平均电子能量有一定的影响,但并不显著。纯氧放电的最佳约化场强为10Td,随着O2含量的降低,最佳约化场强也逐渐降低。平均电子能量随着放电频率的变化先是有一个平台期,然后开始一直下降。用于激发O2(a1Δ)的电子能量利用效率随着放电频率的变化在E/N不同时有所不同,10Td时一直下降,但50Td时则呈现出先上升后下降的趋势,存在着一个最佳放电频率,300K、1333.22Pa时的最佳放电频率为10GHz。
Boltzmann equation is numerically solved for the plasmas generated in the process of discharging of O2, O2/He and O2/Ar in the gas phase. Thereafter, electron energy distribution function, mean electron energy and power efficiency are obtained. The results indicate that electron energy distribution functions are typically non- Maxwellian. For the same reduced electric field （E/N）, the mean electron energy for pure oxygen discharge is lower than O2/He and O2/Ar mixtures. For the same oxygen content, the electron energy distribution function curves versus E/N for 02/He and 02/Ar mixtures cross together. The 02/Ar mixture discharge plasma has higher mean electron energy at lower E/N, while the 02/He mixture has higher mean electron energy at higher GIN. The influence of NO additive gas on the breakdown electric field can be negligible. Therefore, the improvement of O2 （aI A） yield in the presence of NO gas may be not due to the slight decrease of E/N. An addition of 15 % （volume fraction） O2aI A） into O2 causes an increment of the mean electron energy which is not significant. In order to obtain the maximum yield of O2 （a1 A）, the optimum E/N value of pure oxygen discharge plasma is about 10 Td. And the optimum E/N value decreases with the oxygen content. The mean electron energy as a function of the discharge frequency has a long steady baseline before its decrease. The power efficiency for excitation of O2 （a1 A） as a function of discharge frequency has two type curves. It decreases when the E/N is 50 Td. The optimum discharge frequency all the while at 10 Td. However, it rises and then goes down is 10 GHz for the conditions of 300 K and 1333.22 Pa.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2011年第12期42-48,共7页
Chinese Journal of Lasers
基金
国家自然科学基金(10974199)
中国科学院化学激光重点实验室开放课题(KLCL-2011-N4)资助课题
关键词
激光器
化学氧碘激光器
电激励氧碘激光器
玻尔兹曼方程
单重态氧
放电频率
lasers
chemical oxygen iodine laser electric oxygen iodine laser
Boltzmann equation
singlet deltaoxygen O2（a1 A）
discharge frequency
