SCHAEFER, Jan, R. FOEST, Stephan REUTER, Thorben KEWITZ, Jiří ŠPERKA and Klaus-Dieter WELTMANN. Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma. Review of Scientific Instruments. Melville, USA: American Institute of Physics, 2012, vol. 83, No 10, p. 1-8. ISSN 0034-6748. Available from: https://dx.doi.org/10.1063/1.4761924.
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Basic information
Original name Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma
Authors SCHAEFER, Jan, R. FOEST, Stephan REUTER, Thorben KEWITZ, Jiří ŠPERKA (203 Czech Republic, belonging to the institution) and Klaus-Dieter WELTMANN.
Edition Review of Scientific Instruments, Melville, USA, American Institute of Physics, 2012, 0034-6748.
Other information
Original language English
Type of outcome Article in a journal
Field of Study 10300 1.3 Physical sciences
Country of publisher United States of America
Confidentiality degree is not subject to a state or trade secret
WWW Full Text
Impact factor Impact factor: 1.602
RIV identification code RIV/00216224:14310/12:00107120
Organization unit Faculty of Science
Doi http://dx.doi.org/10.1063/1.4761924
UT WoS 000311562500023
Keywords in English REFRACTION MEASUREMENTS; ELECTRON-DENSITY; DEFLECTION; SYSTEMS
Tags rivok
Tags International impact, Reviewed
Changed by Changed by: Mgr. Marie Šípková, DiS., učo 437722. Changed: 20/1/2020 12:41.
Abstract
The heat convection generated by micro filaments of a self-organized non-thermal atmospheric pressure plasma jet in Ar is characterized by employing laser schlieren deflectometry (LSD). It is demonstrated as a proof of principle, that the spatial and temporal changes of the refractive index n in the optical beam path related to the neutral gas temperature of the plasma jet can be monitored and evaluated simultaneously. The refraction of a laser beam in a high gradient field of n(r) with cylindrical symmetry is given for a general real refraction index profile. However, the usually applied Abel approach represents an ill-posed problem and in particular for this plasma configuration. A simple analytical model is proposed in order to minimize the statistical error. Based on that, the temperature profile, specifically the absolute temperature in the filament core, the FWHM, and the frequencies of the collective filament dynamics are obtained for non-stationary conditions. For a gas temperature of 700 K inside the filament, the presented model predicts maximum deflection angles of the laser beam of 0.3 mrad which is in accordance to the experimental results obtained with LSD. Furthermore, the experimentally obtained FWHM of the temperature profile produced by the filament at the end of capillary is (1.5 +/- 0.2) mm, which is about 10 times wider than the visual radius of the filament. The obtained maximum temperature in the effluent is (450 +/- 30) K and is in consistence with results of other techniques. The study demonstrates that LSD represents a useful low-cost method for monitoring the spatiotemporal behaviour of microdischarges and allows to uncover their dynamic characteristics, e. g., the temperature profile even for challenging diagnostic conditions such as moving thin discharge filaments. The method is not restricted to the miniaturized and self-organized plasma studied here. Instead, it can be readily applied to other configurations that produce measurable gradients of refractive index by local gas heating and opens new diagnostics prospects particularly for microplasmas.
Links
CZ.1.05/1.1.00/02.0068, interní kód MUName: CEITEC - středoevropský technologický institut (Acronym: CEITEC)
Investor: Ministry of Education, Youth and Sports of the CR, CEITEC - Central European Institute of Technology, 1.1 European Centres of Excellence
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