Time-resolved characterization of a filamentary argon discharge at atmospheric pressure in a capillary using emission and absorption spectroscopy
Time-resolved characterization of a filamentary argon discharge at atmospheric pressure in a capillary using emission and absorption spectroscopy
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DOI：
10.1088/0022-3727/46/46/464009
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发表时间：
2013-11
期刊：
影响因子：
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通讯作者：
S. Schröter;Ramasamy Pothiraja;P. Awakowicz;N. Bibinov;M. Böke;B. Niermann;J. Winter
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文献类型：
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作者：
S. Schröter;Ramasamy Pothiraja;P. Awakowicz;N. Bibinov;M. Böke;B. Niermann;J. Winter
使用电压-电流测量、显微照相术、光学发射光谱 (OES) 和吸收光谱对石英管中大气压下运行的氩/氮 (0.999/0.001) 丝状脉冲放电进行表征。氮气用作传感器气体，用于 OES 诊断。使用可调谐二极管激光吸收光谱 (TDLAS) 测定氩亚稳态原子 Ar(3P2) 的密度。使用等离子体化学模型，测量的 OES 数据可用于表征等离子体条件。在强烈的正脉冲之间，放电电流以阻尼幅度振荡。可以确定的是，在该放电中电流不仅流过放电图像中观察到的细等离子体丝，而且还流过石英管的整个横截面。在强电流脉冲之间的时间内，扩散等离子体充满石英管。电离波在等离子体中在尖峰和管的接地区域之间传播，产生薄等离子体通道。这些通道的直径在电离波传播之间的暂停期间增加，可能是由于热膨胀和扩散。通道内的电子密度为~2 × 1013 cm−3，氩气亚稳态密度为~1014 cm−3，电场降低约10 Td。
An argon/nitrogen (0.999/0.001) filamentary pulsed discharge operated at atmospheric pressure in a quartz tube is characterized using voltage–current measurements, microphotography, optical emission spectroscopy (OES) and absorption spectroscopy. Nitrogen is applied as a sensor gas for the purpose of OES diagnostic. The density of argon metastable atoms Ar(3P2) is determined using tunable diode laser absorption spectroscopy (TDLAS). Using a plasma chemical model the measured OES data are applied for the characterization of the plasma conditions. Between intense positive pulses the discharge current oscillates with a damped amplitude. It is established that an electric current flows in this discharge not only through a thin plasma filament that is observed in the discharge image but also through the whole cross section of the quartz tube. A diffuse plasma fills the quartz tube during a time between intense current pulses. Ionization waves are propagating in this plasma between the spike and the grounded area of the tube producing thin plasma channels. The diameter of these channels increases during the pause between the propagation of ionization waves probably because of thermal expansion and diffusion. Inside the channels electron densities of ∼2 × 1013 cm−3, argon metastable densities ∼1014 cm−3 and a reduced electric field about 10 Td are determined.