This study determined the electron temperature and density in atmospheric pressure argon plasma using optical emission spectroscopy. The analysis combined continuum and line spectral data. Visible bremsstrahlung inversion was used to derive a partial electron energy probability function (EEPF) from the continuum spectrum. Subsequently, electron temperature was estimated assuming a two-temperature distribution based on the derived EEPF. Electron density was obtained by fitting a collisional-radiative (CR) model to the line spectrum, incorporating the obtained EEPF instead of assuming a Druyvesteynian EEPF. Comparative analysis revealed that the electron densities determined using the approach were approximately one order of magnitude lower than those derived from the CR model with the Druyvesteynian EEPF. However, they exhibited strong agreement with the results obtained by the CR model using a two-temperature distribution. This approach demonstrated favorable performance in reproducing both continuum and line spectra, revealing its high reliability and accuracy for atmospheric pressure argon plasma diagnosis.

1.
T.
Fujimoto
, “
A collisional-radiative model for helium and its application to a discharge plasma
,”
J. Quant. Spectrosc. Radiat. Transfer
21
,
439
(
1979
).
2.
M.
Goto
, “
Collisional-radiative model for neutral helium in plasma revisited
,”
J. Quant. Spectrosc. Radiat. Transfer
76
,
331
(
2003
).
3.
M.
Goto
and
K.
Sawada
, “
Determination of electron temperature and density at plasma edge in the Large Helical Device with opacity-incorporated helium collisional-radiative model
,”
J. Quant. Spectrosc. Radiat. Transfer
137
,
23
(
2014
).
4.
A.
Yanguas-Gil
,
J.
Cortino
, and
A. R.
González-Elipe
, “
Collisional-radiative model for helium and its application to a tokamak plasma
,”
Phys. Plasmas
11
,
5497
(
2004
).
5.
H.
Akatsuka
, “
Excited level populations and excitation kinetics of nonequilibrium ionizing argon discharge plasma of atmospheric pressure
,”
Phys. Plasmas
16
,
043502
(
2009
).
6.
K.
Lin
,
A.
Nezu
, and
H.
Akatsuka
, “
Development of diagnostics of electron density and temperature for atmospheric-pressure helium plasma based on optical emission spectroscopy analysis and a collisional-radiative model
,”
Jpn. J. Appl. Phys., Part 1
62
,
SL1005
(
2023
).
7.
M.
Goto
and
K.
Sawada
, “
Determination of the line emission locations in a large helical device on the basis of the Zeeman effect
,”
Phys. Rev. E
65
,
026401
(
2002
).
8.
K.
Lin
,
M.
Goto
, and
H.
Akatsuka
, “
Improved line intensity analysis of neutral helium by incorporating the reabsorption processes in a helium collisional-radiative model
,”
Atoms
11
,
94
(
2023
).
9.
A.
Sola
,
M. D.
Calzada
, and
A.
Gamero
, “
On the use of the line-to-continuum intensity ratio for determining the electron temperature in a high-pressure argon surface-microwave discharge
,”
J. Phys. D
28
(
6
),
1099
(
1995
).
10.
G. J.
Bastiaans
and
R. A.
Mangold
, “
The calculation of electron density and temperature in Ar spectroscopic plasmas from continuum and line spectra
,”
Spectrochim. Acta Part B
40
(
7
),
885
(
1985
).
11.
S.
Ham
,
J.
Ryu
,
H.
Lee
,
S.
Park
,
Y.
Ghim
,
Y. S.
Hwang
, and
K.
Chung
, “
Estimation of plasma parameters of X-pinch with time-resolved x-ray spectroscopy
,”
Matter Radiat. Extremes
8
,
036901
(
2023
).
12.
K. T. A. L.
Burm
, “
Continuum radiation in a high pressure argon–mercury lamp
,”
Plasma Sources Sci. Technol.
13
,
387
(
2004
).
13.
S.
Park
,
W.
Choe
,
S.
Youn Moon
, and
J.
Park
, “
Electron density and temperature measurement by continuum radiation emitted from weakly ionized atmospheric pressure plasmas
,”
Appl. Phys. Lett.
104
,
084103
(
2014
).
14.
S.
Park
,
W.
Choe
,
H.
Kim
, and
J. Y.
Park
, “
Continuum emission-based electron diagnostics for atmospheric pressure plasmas and characteristics of nanosecond-pulsed argon plasma jets
,”
Plasma Sources Sci. Technol.
24
,
034003
(
2015
).
15.
L. S.
Frost
and
A. V.
Phelps
, “
Momentum-transfer cross sections for slow electrons in He, Ar, Kr, and Xe from transport coefficients
,”
Phys. Rev.
136
,
A1538
(
1964
).
16.
H.
Onishi
,
F.
Yamazaki
,
Y.
Hakozaki
,
M.
Takemura
,
A.
Nezu
, and
H.
Akatsuka
, “
Measurement of electron temperature and density of atmospheric-pressure non-equilibrium argon plasma examined with optical emission spectroscopy
,”
Jpn. J. Appl. Phys., Part 1
60
,
026002
(
2020
).
17.
T.
van der Gaag
,
A.
Nezu
, and
H.
Akatsuka
, “
Partial EEDF analysis and electron diagnostics of atmospheric-pressure argon and argon–helium DBD plasma
,”
J. Phys. D
56
,
304001
(
2023
).
18.
S.
Jaiswal
,
E. M.
Aguirre
, and
T.
van der Gaag
, “
Characterization of an atmospheric pressure plasma jet producing the auroral transition O (1S) to O (1D)
,”
Plasma Sources Sci. Technol.
31
(
12
),
125011
(
2022
).
19.
A.
Savitzky
and
M. J. E.
Golay
, “
Smoothing and differentiation of data by simplified least squares procedures
,”
Anal. Chem.
36
,
1627
(
1964
).
20.
T.
van der Gaag
,
A.
Nezu
, and
H.
Akatsuka
, “
Practical considerations of the visible bremsstrahlung inversion (VBI) method for arbitrary EEDF determination in cold
,”
Jpn. J. Appl. Phys., Part 1
61
,
076004
(
2022
).
21.
T.
van der Gaag
,
H.
Onichi
, and
H.
Akatsuka
, “
Arbitrary EEDF determination of atmospheric-pressure plasma by applying machine learning to OES measurement
,”
Phys. Plasmas
28
,
033511
(
2021
).
22.
H.
Akatsuka
, “
Optical emission spectroscopic (OES) analysis for diagnostics of electron density and temperature in high-pressure non-equilibrium plasmas
,”
Oyobuturi
87
,
821
(
2018
) (in Japanese).
23.
H.
Akatsuka
, “
Optical emission spectroscopy measurement of processing plasmas
,”
IEEJ Trans. Fundam. Mater.
13
,
892
(
2010
) (in Japanese).
24.
T.
Fujimoto
,
Plasma Spectroscopy
(
Clarendon
,
Oxford
,
2004
).
25.
G. J. M.
Hagelaar
and
L. C.
Pitchford
, “
Solving the Boltzmann equation to obtain electron transport coefficients and rate coefficients for fluid models
,”
Plasma Sources Sci. Technol.
14
,
722
(
2005
).
26.
L.
Qin
and
O.
Li
, “
Recent progress of low-temperature plasma technology in biorefining process
,”
Nano Convergence
10
,
38
(
2023
).
27.
H.
Zhao
,
X.
Wang
,
Z.
Liu
,
Y.
Wang
,
L.
Zou
,
Y.
Chen
, and
Q.
Han
, “
The effect of argon cold atmospheric plasma on the metabolism and demineralization of oral plaque biofilms
,”
Front. Cell. Infect. Microbiol.
13
,
1116021
(
2023
).
28.
H.
Shabani
,
A.
Dezhpour
,
S.
Jafari
,
M. J.
Mehdipour Moghaddam
, and
M.
Nilkar
, “
Antimicrobial activity of cold atmospheric-pressure argon plasma combined with chicory (Cichorium intybus L.) extract against P. aeruginosa and E. coli biofilms
,”
Sci. Rep.
13
,
9441
(
2023
).
29.
T. P.
Radhika
and
S.
Kar
, “
Effect of an additional floating electrode on radio frequency cross-field atmospheric pressure plasma jet
,”
Sci. Rep.
13
,
10665
(
2023
).
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