Simple and quick rotational temperature determination in N2-containing discharge plasma

1993 ◽  
Vol 13 (3) ◽  
pp. 567-577 ◽  
Author(s):  
J. Janča ◽  
L. Skrřička ◽  
A. Brablec
Keyword(s):  
Discharge Plasma ◽  
Rotational Temperature ◽  
Temperature Determination

Measurement of vibrational and rotational temperature in spark-discharge plasma by optical emission spectroscopy: Change in thermal equilibrium characteristics of plasma under air flow

2018 ◽  
Vol 20 (7) ◽  
pp. 746-757 ◽  
Author(s):  
Masao Kinoshita ◽  
Takayuki Fuyuto ◽  
Hiroshi Akatsuka
Keyword(s):  
Thermal Equilibrium ◽  
Optical Emission Spectroscopy ◽  
Discharge Plasma ◽  
Vibrational Temperature ◽  
Rotational Temperature ◽  
Air Flow ◽  
Optical Emission ◽  
Spark Discharge ◽  
Spark Plug ◽  
Spark Discharge Plasma

The vibrational and rotational temperatures in a spark-discharge plasma were measured using optical emission spectroscopy, and the influence of the air flow velocity and ambient pressure on these temperatures was investigated. The optical emissions from the plasma were led to an imaging spectroscope through an optical fiber. The temperature was estimated by fitting a theoretically calculated spectrum to that which had been acquired experimentally, formed by nitrogen molecule emission from 372 to 382 nm. The spark-discharge plasma was examined with a flow of ambient air at a discharge energy of 80 mJ. The air flow caused the spark-discharge channel to elongate downstream. At the center of the spark plug gap, the vibrational temperature in the plasma was 4000 K, whereas the rotational temperature was 2000 K. This plasma can be regarded as being in non-thermal equilibrium because the vibrational temperature was higher than the rotational temperature. At a position approximately 3 mm downstream from the spark plug gap, the vibrational and rotational temperatures increased to 4500 and 4000 K, respectively, while approaching each other. Both temperatures reached a maximum value. These results show that the plasma transitions from non-thermal equilibrium to thermal equilibrium as it is elongated by the air flow. Ignition efficiency improvements can be expected if the time required to transition from non-thermal to thermal equilibrium can be shortened.

scholarly journals Hydroxyl (6–2) airglow emission intensity ratios for rotational temperature determination

2000 ◽  
Vol 18 (10) ◽  
pp. 1293-1303
Author(s):  
W. J. R. French ◽  
G. B. Burns ◽  
K. Finlayson ◽  
P. A. Greet ◽  
R. P. Lowe ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Rotational Temperature ◽  
Airglow Emission ◽  
Temperature Determination ◽  
Intensity Ratios

scholarly journals Hydroxyl (6−2) airglow emission intensity ratios for rotational temperature determination

2000 ◽  
Vol 18 (10) ◽  
pp. 1293-1303 ◽  
Author(s):  
W. J. R. French ◽  
G. B. Burns ◽  
K. Finlayson ◽  
P. A. Greet ◽  
R. P. Lowe ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Transition Probabilities ◽  
Rotational Temperature ◽  
Atmospheric Composition ◽  
Rotational States ◽  
Airglow Emission ◽  
Temperature Determination ◽  
Atmospheric Composition And Structure ◽  
Composition And Structure ◽  
Intensity Ratios

Abstract. OH(6–2) Q1/P1 and R1/P1 airglow emission intensity ratios, for rotational states up to j' = 4.5, are measured to be lower than implied by transition probabilities published by various authors including Mies, Langhoff et al. and Turnbull and Lowe. Experimentally determined relative values of j' transitions yield OH(6–2) rotational temperatures 2 K lower than Langhoff et al., 7 K lower than Mies and 13 K lower than Turnbull and Lowe.Key words: Atmospheric composition and structure (airglow and aurora; pressure, density and temperature)

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