约化场强对氮-氧混合气放电等离子体演化特性的影响

采用零维等离子体动力学模型,计算了不同约化场强条件下N₂/O₂放电等离子体的演化特性.结果表明,平均电子能量与约化场强有着近似的线性关系,在约化场强为100 Td时,平均电子能量约为2.6 eV、最大电子能量达35 eV;约化场强是影响电子能量函数分布的主要因素.气体放电过程结束后,振动激发态氮分子的粒子数浓度不再变化,电子激发态的氮分子、原子和氧原子的粒子数浓度达到一峰值后开始降低;放电结束后的氧原子通过复合反应生成臭氧.约化场强升高,由于低能电子减少的影响,振动激发态氮分子的粒子数浓度降低,当约化场强由50 Td增加75 Td,100 Td时,粒子数浓度由3.83×10¹¹ cm^-3降至1.98×10¹¹ cm^-3和1.77×10¹¹ cm^-3,其他粒子浓度则相应增大. 关键词： 等离子体 约化场强 粒子演化 数值模拟

Influence of reduced electric field on the evolvement characteristics of plasma under conditions of N2/O2 discharge

Adopting the plasma kinetic model, we perform a numerical calculation of evolution characteristics in N₂/O₂ plasma with various reduced electric fields. The results show that there is an approximate linear relation between electron average energy and reduced electric field, the electron average energy is 2.6 eV and its maximum is 35 eV when reduced electric field is 100 Td, and reduced electric field has a strong influence on electron energy distributing function. The number densities of nitrogen molecules and atoms, oxygen atoms in electronic excited state reach their peaks when discharge is over, then drop off; but the number density of nitrogen molecules in vibrational excitation remains unchanged after discharge; oxygen atoms recombine into ozone molecules. With the increase of reduced electric field, the number density of vibration excitated nitrogen molecules reduces because of the decrease of the number of electrons with low energy, but other particles are increasing. The number densities of vibrational excitated nitrogen molecules are 3.83×10¹¹cm^-3, 1.98×10¹¹cm^-3 and 1.77×10¹¹ cm^-3 when reduced electric fields are set to be 50 Td, 75 Td and 100 Td respectively.