Transient current and sheath motion following the photoelectron-initiated avalanche in dc glow discharges.
Transient current and sheath motion following the photoelectron-initiated avalanche in dc glow discharges.
复制标题
直流辉光放电中光电子引发雪崩后的瞬态电流和鞘层运动。
DOI：
10.1103/physreva.40.5208
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Boeuf
中科院分区：
文献类型：
--
作者：
Debontride;Derouard;Edel;Romestain;Sadeghi;Boeuf
我们已经进行了时间分辨的观察电流，光发射，和电场分布在Ar +2%K直流辉光放电，脉冲激光诱导光电子发射的阴极。这些观察结果表明：（1）光电子引发的雪崩导致放电中电荷分布的强烈扰动。这可以观察到鞘管长度显著缩短。(2)这使得放电处于非稳态状态，具有高度增强的电导。然后，它会松弛到初始的稳态状态，在我们的条件下，这个时间大约是100 \ensuremath{\mu}s。这一时间比鞘层中的离子渡越时间大得多，也比双极扩散时间短。自洽的宏观模拟已经完成，并发现是在良好的定性协议与观察。还进行了鞘层电离的Monte Carlo微观模拟，指出了自洽模拟中使用的“束模型”的一些缺点。
We have performed time-resolved observations of the current, optical emission, and electric field profiles in an Ar +2% K dc glow discharge, following the pulsed-laser-induced photoelectron emission on the cathode. These observations indicate that (1) The photoelectron-initiated avalanche results in a strong perturbation of the charge distribution in the discharge. This can be observed as a considerable shortening of the sheath length. (2) This leaves the discharge in a nonstationary regime, with a highly enhanced conductance. It then relaxes to the initial, steady-state regime in a time which is about 100 \ensuremath{\mu}s in our conditions. This time is both considerably larger than the ion transit time in the sheath and shorter than the ambipolar diffusion time. Self-consistent macroscopic simulations have been done and found to be in excellent qualitative agreement with the observations. Monte Carlo microscopic simulations of the ionization in the sheath have also been performed to point out some shortcomings of the ``beam model'' used in the self-consistent simulations.