Diagnostic of Ar-CO2 mixture plasma using a fine-structure resolved collisional radiative model

Shukla, Neelam; Gangwar, Reetesh Kumar; Srivastava, Rajesh

doi:10.1016/j.sab.2020.106019

Cited by 4 publications

(2 citation statements)

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“…[17] In this light, the present work focuses on the development of a fine-structure resolved CR model for Ne-Ar mixture plasma. Earlier, our group reported various diagnostic studies on pure [18][19][20] and mixture rare gas plasma [21][22][23] through developing CR models. To develop these CR models, the detailed calculation of electron impact excitations (EIEs) cross-sections among various fine-structure levels was also carried out using fully relativistic distorted wave (RDW) approximation.…”

Section: Introductionmentioning

confidence: 99%

Diagnostics of Ne–Ar mixture plasma using a fine‐structure resolved collisional radiative model

Baghel

Gangwar

Srivastava

2022

Contributions to Plasma Physics

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A collisional radiative (CR) model has been developed for the diagnostics of Ne-Ar mixture plasma. The 40 fine-structure resolved energy levels of neon corresponding 2p 5 3s, 2p 5 3p, 2p 5 3d, 2p 5 4s, and 2p 5 4p along with ground state (2p 6 ) and ion state (2p 5 ) have been considered. All the essential population and de-population channels viz. electron impact excitation-de-excitation, ionization, two/three-body recombination, radiative decay, self-absorption correction, diffusion, etc., have been considered in the model. The quenching of relatively higher lifetime states 2p 5 3s due to interaction with Ar atoms through associative and Penning ionization is also included in the model. The applicability of the CR model is demonstrated by performing the optical diagnostic of rf induced inductively coupled Ne-Ar mixture plasma. The plasma parameters viz. electron temperature, electron density, and population distribution of levels at various mixture conditions are extracted by coupling the present CR model predictions with emission and absorption measurements by Boffard et al. [J. Phys. D: Appl. Phys., 45, 382001 (2012) and private communication]. The results are also compared with earlier optical models and Langmuir probe measurements.The self-absorption correction (escape) factors and electron impact excitation rates at various Ne-Ar mixture concentrations are also presented.

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Section: Introductionmentioning

confidence: 99%

Diagnostics of Ne–Ar mixture plasma using a fine‐structure resolved collisional radiative model

Baghel

Gangwar

Srivastava

2022

Contributions to Plasma Physics

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“…CR models coupled with suitable OES measurements provide detailed information about plasma parameters, metastable populations, etc. Many of the earlier diagnostic studies through CR models have mainly focused on pure rare gas plasma [18][19][20] or a few on argon discharges with molecular admixtures [17,[21][22][23]. Priti et al [23] have used CR model to diagnose low-pressure rf generated Ar plasma with small admixture of oxygen (0%-5%).…”

Section: Introductionmentioning

confidence: 99%

Diagnostic study of capacitively coupled neon rf plasma with traces of O₂/H₂ at intermediate pressure

Baghel¹,

Şahi̇n²,

Agrawal³

et al. 2022

J. Phys. D: Appl. Phys.

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We have performed the non-invasive diagnostic study of capacitively coupled Ne-O2/H2 mixture plasma through the Optical emission spectroscopy (OES) coupled with a suitable Collisional Radiative (CR) model. Capacitively coupled neon radio-frequency (rf) discharge (flowing downstream) with small admixture of O2/H2 have been generated in a vacuum chamber using 13.56 MHz rf signal and 120 W power supply. Keeping O2 and H2 flow rates fixed at 0.01 and 0.015 LPM respectively, the neon flow rate has been varied as 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 LPM to obtain different mixture concentration of Ne-O2 and Ne-H2 discharge. The pressure in the chamber has been observed in intermediate range (~500-25000 Pa) for different mixture concentrations. Optical emission spectroscopy (OES) measurements are recorded at various operating conditions in the wavelength range from 200 nm to 1200 nm. To extract the information of plasma parameters from the OES measurements, a comprehensive fine-structure resolved collisional radiative (CR) model has been developed. In the diagnostic process, five intense Ne-I emission lines at 594.48, 607.43, 633.44, 638.30, 703.24 nm are used. The CR model considers all the important processes i.e. electron impact excitation, electron impact de-excitation, radiative decay, ionization, two-three body recombination, and diffusion. The quenching process of 1s (1s5,1s4,1s3) levels of neon by the O2/H2 molecule has been included in the model. Radiative transitions from the upper levels to the ground state (1S0) and to the 1s levels of neon are corrected for self-absorption. The electron temperature (Te) and electron density (ne) of the plasma have been extracted for all the mixture concentrations of Ne-O2 and Ne-H2. With the different mixture concentrations of O2/H2 in neon discharge, the variation of population of metastable levels (1s5, 1s3) of neon and intensities of 656.28 nm of hydrogen and 777.4 nm of oxygen lines have been reported and discussed.

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Combination of optical emission spectroscopy and multivariate data analysis techniques as a versatile non-invasive tool for characterizing xenon/krypton mixed gas plasma inside operating ion thrusters

Nauschütt

Chen

Holste

et al. 2022

Journal of Applied Physics

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Non-invasive assessment of the plasma parameters is a useful tool for a reliable characterization of many electric thrusters for space applications. Due to high costs, limited availability, and growing use of electric propulsion in spaceflight, alternatives to Xe as a propellant are becoming increasingly important. One option is to use the lighter noble gas krypton or xenon/krypton gas mixtures as a propellant. We propose a versatile analytical approach for establishing empirical correlations between plasma parameters and optical emission (OE) spectroscopy utilizing principal component analysis (PCA). Our approach allows us to establish a surjective mapping of individual OE spectra via their PCA scores onto the corresponding plasma parameters. We prove the feasibility of this approach for Xe, Kr, and Xe/Kr mixed plasmas demonstrating that it is applicable for a wide range of propellant candidates. A major advantage is that the approach does not rely on any microscopic modeling of the OE spectra of the plasma. After having established corresponding reference mappings, the approach can be explored for determining non-invasively and spatially resolved plasma parameters of the propellant plasma of various kinds of operating ion thrusters, which operate in the same plasma regime as the reference plasma. Thus, this method may contribute to shorter qualification and testing times of ion thrusters.

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Diagnostic of Ar-CO2 mixture plasma using a fine-structure resolved collisional radiative model

Cited by 4 publications

References 46 publications

Diagnostics of Ne–Ar mixture plasma using a fine‐structure resolved collisional radiative model

Diagnostics of Ne–Ar mixture plasma using a fine‐structure resolved collisional radiative model

Diagnostic study of capacitively coupled neon rf plasma with traces of O₂/H₂ at intermediate pressure

Combination of optical emission spectroscopy and multivariate data analysis techniques as a versatile non-invasive tool for characterizing xenon/krypton mixed gas plasma inside operating ion thrusters

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Diagnostic of Ar-CO2 mixture plasma using a fine-structure resolved collisional radiative model

Cited by 4 publications

References 46 publications

Diagnostics of Ne–Ar mixture plasma using a fine‐structure resolved collisional radiative model

Diagnostics of Ne–Ar mixture plasma using a fine‐structure resolved collisional radiative model

Diagnostic study of capacitively coupled neon rf plasma with traces of O2/H2 at intermediate pressure

Combination of optical emission spectroscopy and multivariate data analysis techniques as a versatile non-invasive tool for characterizing xenon/krypton mixed gas plasma inside operating ion thrusters

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Diagnostic study of capacitively coupled neon rf plasma with traces of O₂/H₂ at intermediate pressure