OH concentration and temperature measurements by femtosecond cavity enhanced absorption spectroscopy in a nanosecond-pulsed dielectric barrier discharge

Ning Liu, Hongtao Zhong, Ying Lin, Timothy Y. Chen, Ziyu Wang, Yiguang Ju

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

In many low temperature plasmas, the OH radical and temperature represent important properties of plasma reactivity. However, experimentally measuring OH radicals in weakly ionized low temperature plasmas is often difficult because of its low concentration, posing a significant challenge to diagnostics. To address such issue, this work combines cavity enhanced absorption spectroscopy (CEAS) with femtosecond (fs) laser to simultaneously measure OH concentration and temperature in-situ in low temperature plasmas. This combination has two major benefits. First, the CEAS technique featuring a low detection limit can be used to measure low-concentration OH radicals in the weakly ionized low temperature plasma environment. Second, the broadband fs laser further provides CEAS with many absorption features as constraints, such that simultaneous measurements of OH concentration and temperature can be enabled with improved accuracy. In this work, the fs CEAS was demonstrated on OH both numerically and experimentally in plasmas generated by a nanosecond-pulsed dielectric barrier discharge. The results showed that, at OH concentration down to 0.05 ppm, the fs CEAS could achieve a 0.5% measurement error for OH concentration and a 0.2% error for temperature. This illustrated the benefits of low detection limit and high-accuracy simultaneous measurements brought about by combining CEAS with fs laser.

Original languageEnglish (US)
Title of host publicationAIAA SciTech Forum 2022
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624106316
DOIs
StatePublished - 2022
EventAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 - San Diego, United States
Duration: Jan 3 2022Jan 7 2022

Publication series

NameAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022

Conference

ConferenceAIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022
Country/TerritoryUnited States
CitySan Diego
Period1/3/221/7/22

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering

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