open access

https://hdl.handle.net/2115/93973

Detection of negative ions in streamer discharge in air by transient cavity ringdown spectroscopy

英語

transient cavity ringdown spectroscopy

2024-02-02

IOP Publishing

Plasma Sources Science and Technology

33(2)

02LT01

Atmospheric-pressure discharges generated in air are expected to be electronegative, but experiments that examine negative ion densities are limited to date. In this work, we measured the temporal variation of the negative ion density in a streamer discharge generated in air. We adopted cavity ringdown spectroscopy, where negative ions were detected via weak optical absorption caused by laser photodetachment. The temporal variation of the absolute negative ion density was deduced by the transient analysis of the ringdown curve. Negative ions were detected after the disappearance of the discharge voltage and current. The negative ion density started the increase at 0.4 mu s after the initiation of the discharge. The increase means the enhancement of the electron attachment frequency in the late phase of the secondary streamer with electron cooling. The survival of electrons until 0.4 mu s is understood by the steep decrease in the cross section of dissociative recombination with the electron energy. The maximum negative ion density was observed at 1 mu s, and it was around the noise level at 1.5 mu s. The rapid decay is consistent with the destruction of negative ions by mutual neutralization with positive ions.

学術雑誌論文

Accepted Manuscript

Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

This is the Accepted Manuscript version of an article accepted for publication in Plasma Sources Science and Technology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://doi.org/10.1088/1361-6595/ad227e.

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