高气压直流辉光CH_4/H_2等离子体放电过程中的占空比效应
Effect of Duty Ratio on High Pressure DC Glow Discharge of CH_4/H_2 Plasma
查看参考文献8篇
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文摘
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对高气压下直流均匀辉光放电的脉冲占空比效应进行了研究。在1.7 kHz脉冲放电条件下,当占空比高于73 %时,脉冲间隔后电压需要经过10 ~20 µs的上升时间至稳定;而电流增长明显地滞后于电压的上升,整个增长过程需要的时间约是电压上升时间的10倍。减小占空比,表示电流增长快慢程度的时间常数τ几乎线性增加。这是因为小占空比时,上升通道开始时刻的等离子体电子密度低,放电电流需要更长时间才能稳定。在高气压条件下,粒子碰撞效应显著增强,增加的放电功率被更多地被用于加热中性粒子,表现为H_a、H_β等发射光谱强度随占空比降低而增加。进一步减小占空比,电子密度ne衰减到过低,时间常数τ增加到一定值时,放电就难以维持,表现为放电不稳定乃至熄灭。 |
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其他语种文摘
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The effect of duty-ratio on the characteristics of high pressure DC glow discharge of CH_4/H_2 plasma was investigated by monitoring the current/voltage waveforms and diagnosis of plasma emission spectrum. The results show that the duty-ratio has a major impact. For instance, with a duty-ratio above 73% at 1. 7 kHz, it took 10 ~20 ms( 100~ 200 ms) of rising time for the voltage ( current) to be stable. The current increased with the increasing discharge voltage in a rapid-slow manner, considerably lagging behind the voltage. As the duty-ratio decreased ,the time constant increased almost linearly,because smaller duty-ratio produced lower electron density at the beginning of ascending channel. At a high pressure, as the duty-ratio decreased, the H_a and H_β emission intensities increased because the increased discharge power heated neutral particles, significantly promoting particle collision. A duty-ratio too small reduced the e-density and increased the time constant,resulting in an unstable or quenched discharge. |
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来源
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真空科学与技术学报
,2019,39(5):429-433 【扩展库】
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DOI
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10.13922/j.cnki.cjovst.2019.05.12
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关键词
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高气压直流等离子体
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占空比
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波形
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发射光谱
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地址
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1.
中国科学技术大学物理学院, 合肥, 230026
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中国科学院等离子体物理研究所, 合肥, 230031
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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1672-7126 |
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学科
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物理学 |
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基金
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国家重点研发计划
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国家自然科学基金项目
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文献收藏号
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CSCD:6501933
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