Thomson scattering versus modeling of the microwave plasma torch: a long standing discrepancy almost solved

VAN DER MULLEN, Joost, Mariana ATANASOVA, Adam OBRUSNÍK and Lenka ZAJÍČKOVÁ. Thomson scattering versus modeling of the microwave plasma torch: a long standing discrepancy almost solved. Journal of analytical atomic spectrometry. Cambridge: Royal Society of Chemistry, 2020, vol. 35, No 9, p. 2064-2074. ISSN 0267-9477. Available from: https://dx.doi.org/10.1039/d0ja00161a.

Basic information

• Original name: Thomson scattering versus modeling of the microwave plasma torch: a long standing discrepancy almost solved
• Authors: VAN DER MULLEN, Joost, Mariana ATANASOVA, Adam OBRUSNÍK (203 Czech Republic, belonging to the institution) and Lenka ZAJÍČKOVÁ (203 Czech Republic, belonging to the institution).
• Edition: Journal of analytical atomic spectrometry, Cambridge, Royal Society of Chemistry, 2020, 0267-9477.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10305 Fluids and plasma physics
• Country of publisher: United Kingdom of Great Britain and Northern Ireland
• Confidentiality degree: is not subject to a state or trade secret
• WWW: URL
• Impact factor: Impact factor: 4.023
• RIV identification code: RIV/00216224:14310/20:00117958
• Organization unit: Faculty of Science
• Doi: http://dx.doi.org/10.1039/d0ja00161a
• UT WoS: 000569703600027
• Keywords in English: plasma torches; light emission; microwaves
• Tags: rivok
• Tags: International impact, Reviewed

Abstract

The characterization of plasmas gives much more insight if the results of modeling are compared with those of experiments. In the past, several modeling-experiment studies were performed on the microwave plasma torch (MPT). For the modeling a Global Plasma Model (GPM) was employed and for the experiment Thomson scattering (TS) was used. The same GPM-TS comparison was successfully applied to several other, more robust plasmas. However for the MPT it was found that the comparison led to severe discrepancies. The most salient feature was that the value of the electron temperature,T-e, found by TS, was substantially higher than what GPMs predicted. Several attempts were undertaken to solve this problem by refining the model and its most important input: the gradient of the electron density. The attention for the model implied that the TS technique was not scrutinized sufficiently. Recently it was discovered that the outcome of TS is very sensitive to the spectral fitting procedure. In the past this was carried out by employing the calibrated intensity using Gaussian fitting. However, a procedure based on the fitting of the spectral shape by using modified Gaussian fitting gives better results and leads to a lowerT(e)value, more in the range of the GPM results. This paper discusses the background of the GPM and gives the basis of TS fitting procedures and an analysis of the systematic error that can be made when TS is performed on filamentary MPT-like plasmas.

Links

• LQ1601, research and development project: Name: CEITEC 2020 (Acronym: CEITEC2020)

Investor: Ministry of Education, Youth and Sports of the CR