Gas discharge plasmas generated by μs-pulse focused microwaves are investigated.The model is based on a self-consistent solution to Helmholtz equation for microwave field,particle continuity equations,and the energy balance equations, coupled with plasma kinetics.Two recent experiments are studied:a.sub-megawatt (MW)X-band 9.4 GHz microwave break-down in nitrogen;b.MW-class W-band 110 GHz microwave breakdown in 100-10 000 Pa air.In experiment a,the tracked densi-ty of electronic states N2(C3Πu)agreed with the measured intensity from second positive system (SPS)of optical emission spec-troscopy (OES).In experiment b,the simulation results reproduced the dependence of nitrogen vibrational and translational tem-perature on air pressure measured by OES.The underlying mechanisms for the above coincidences are unveiled.%研究了微秒脉冲聚焦微波束气体放电等离子体的动理学过程.数值模型基于自洽求解的微波电场亥姆霍兹方程、粒子连续性方程以及电子能量、气体分子振动能量和平动能量的平衡方程,并与等离子体动理学反应互相耦合.对比了国外报道的近期两项相关实验:次 MW 级 X 波段9.4 GHz 微波氮气击穿和MW级W波段110 GHz微波大气击穿.在次MW级实验中,计算所得电子激发态N2(C3Πu)的数密度与实验所测发射光谱第二正带隙的强度一致;在 MW级实验中,模拟结果重复了发射光谱测量所得振动温度和平动温度对放电气压的依赖关系.结果揭示了上述模拟和实验符合的内在物理机制.
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