Spectroscopic Study on Vibrational Nonequilibrium of a Microwave Discharge Nitrogen Plasma
Spectroscopic Study on Vibrational Nonequilibrium of a Microwave Discharge Nitrogen Plasma
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DOI：
10.1143/jjap.43.5550
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发表时间：
2004-08
影响因子：
1.5
通讯作者：
S. Koike;T. Sakamoto;H. Kobori;H. Matsuura;H. Akatsuka
中科院分区：
文献类型：
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作者：
S. Koike;T. Sakamoto;H. Kobori;H. Matsuura;H. Akatsuka
我们使用矩形波导和沿电场矢量插入的石英管（直径30 mm）产生微波放电氮等离子体，并带有可调节的短路柱塞。典型放电条件为：微波频率2.45 GHz，输入功率550w，氮气（99.5%）气体流速0.01 ~ 1.6 l/min，放电压力p=0.5 ~ 10 Torr。用双探针测量电子温度Te和密度ne。振动温度Tv是由N2 - C的振动激发态3Πu的居群密度通过光谱分析得到的。旋转温度Tr由实验观测到的振动谱与计算得到。研究发现，在当前压力条件下，Te≃0.5-2 eV, Tv≃0.45-1 eV, Tr≃0.06-0.1 eV，低放电压力下，ne≃1011-1012 cm-3，高放电压力下，ne≃108-109 cm-3。我们通过理论计算讨论了测量到的振动居群，其中它们的数量密度变化用氮等离子体中的分子过程来表示。
We generate a microwave discharge nitrogen plasma using a rectangular waveguide and a quartz tube (30 mm i.d.) inserted along the vector of the electric field, with an adjustable short-circuited plunger. The typical discharge conditions used are as follows: microwave frequency 2.45 GHz, input power 550 W, nitrogen (99.5%) gas flow rate 0.01–1.6 l/min, and discharge pressure p=0.5–10 Torr. Electron temperature Te, and density ne are measured using a double probe. Vibrational temperature Tv is obtained from the population density of the vibrational exited states of N2 C 3Πu by spectroscopic examination. Rotational temperature Tr is obtained from a comparison of the rovibronic spectra observed experimentally with the calculated ones. It is found that Te≃0.5–2 eV, Tv≃0.45–1 eV, and Tr≃0.06–0.1 eV under the present pressure conditions, whereas ne≃1011–1012 cm-3 at a low discharge pressure, and ne≃108–109 cm-3 at a high discharge pressure. We discuss the measured vibrational populations by theoretical calculations in which the variation in their number density is expressed in terms of molecular processes in the nitrogen plasma.