scholarly journals Study by Optical Spectroscopy of Bismuth Emission in a Nanosecond-Pulsed Discharge Created in Liquid Nitrogen

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7403
Author(s):  
Anna V. Nominé ◽  
Cédric Noel ◽  
Thomas Gries ◽  
Alexandre Nominé ◽  
Valentin A. Milichko ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Liquid Nitrogen ◽  
Electron Density ◽  
Optical Emission ◽  
Time Resolved ◽  
Main Discharge ◽  
Temperature Electron ◽  
Discharge Parameters ◽  
Pulsed Discharges ◽  
Bismuth Electrodes

Time-resolved optical emission spectroscopy of nanosecond-pulsed discharges ignited in liquid nitrogen between two bismuth electrodes is used to determine the main discharge parameters (electron temperature, electron density and optical thickness). Nineteen lines belonging to the Bi I system and seven to the Bi II system could be recorded by directly plunging the optical fibre into the liquid in close vicinity to the discharge. The lack of data for the Stark parameters to evaluate the broadening of the Bi I lines was solved by taking advantage of the time-resolved information supported by each line to determine them. The electron density was found to decrease exponentially from 6.5 ± 1.5 × 1016 cm−3 200 ns after ignition to 1.0 ± 0.5 × 1016 cm−3 after 1050 ns. The electron temperature was found to be 0.35 eV, close to the value given by Saha’s equation.

scholarly journals Machine Learning Prediction of Electron Density and Temperature from Optical Emission Spectroscopy in Nitrogen Plasma

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1221
Author(s):  
Jun-Hyoung Park ◽  
Ji-Ho Cho ◽  
Jung-Sik Yoon ◽  
Jung-Ho Song
Keyword(s):  
Machine Learning ◽  
Electron Temperature ◽  
Real Time ◽  
Electron Density ◽  
Emission Spectroscopy ◽  
Optical Emission Spectroscopy ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Plasma Nitridation

We present a non-invasive approach for monitoring plasma parameters such as the electron temperature and density inside a radio-frequency (RF) plasma nitridation device using optical emission spectroscopy (OES) in conjunction with multivariate data analysis. Instead of relying on a theoretical model of the plasma emission to extract plasma parameters from the OES, an empirical correlation was established on the basis of simultaneous OES and other diagnostics. Additionally, we developed a machine learning (ML)-based virtual metrology model for real-time Te and ne monitoring in plasma nitridation processes using an in situ OES sensor. The results showed that the prediction accuracy of electron density was 97% and that of electron temperature was 90%. This method is especially useful in plasma processing because it provides in-situ and real-time analysis without disturbing the plasma or interfering with the process.

scholarly journals Physical conditions in H II galaxies

2003 ◽  
Vol 212 ◽  
pp. 722-723
Author(s):  
Carolina Kehrig ◽  
Eduardo Telles ◽  
François Cuisinier
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Statistical Properties ◽  
Chemical Abundances ◽  
Physical Conditions ◽  
Temperature Electron

We present a spectrophotometric survey of 111 H ii galaxies. Observations were made at the ESO 1.52m telescope, with the b&c spectrograph. Our sample presents a great overlap with Terlevich et al. 1991. Additional targets come from the Calan-Tololo an Marseille catalogues. All objects have been observed and analysed homogeneously. We analyse their statistical properties and derive physical conditions (reddening, electron temperature, electron density), as well as chemical abundances.

scholarly journals Analysis of Observations near the Fourth Electron Gyrofrequency Heating Experiment in EISCAT

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 191
Author(s):  
Zeyun Li ◽  
Hanxian Fang ◽  
Hongwei Gong ◽  
Zhe Guo
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Parametric Instability ◽  
Density Fluctuations ◽  
Lower Hybrid ◽  
Langmuir Waves ◽  
Ionospheric Heating ◽  
Superthermal Electron ◽  
Temperature Electron ◽  
Electron Gyrofrequency

We present the observations of the artificial ionospheric heating experiment of EISCAT (European Incoherent Scatter Scientific Association) on 22 February 2012 in Tromsø, Norway. When the pump is operating near the fourth electron gyrofrequency, the UHF radar observation shows some strong enhancements in electron temperature, electron density, ion line, and the outshifted plasma lines. Based on some existing theories, we find the following: first, Langmuir waves scattering off lower hybrid density fluctuations and strong Langmuir turbulence (SLT) in the Zakharov model cannot completely explain the outshifted plasma lines, but the data suggest that this phenomenon is related to the cascade of the pump wave and should be researched further; second, the spatiotemporal consistency between the enhancement in electron density/electron temperature reaches up to three to four times that of the undisturbed state and HF-enhanced ion lines (HFILs) suggest that SLT excited by parametric instability plays a significant role in superthermal electron formation and electron acceleration; third, some enhancements in HFILs and HF-induced plasma lines (HFPLs) are generated by parametric decay instability (PDI) during underdense heating in the third cycle, we suggest that this is due to the existence of a second cut-off in the upper hybrid dispersion relation as derived from a kinetic description.

Time-resolved electron density and electron temperature measurements in nanosecond pulse discharges in helium

2016 ◽  
Vol 25 (5) ◽  
pp. 055009 ◽  
Author(s):  
A Roettgen ◽  
I Shkurenkov ◽  
M Simeni Simeni ◽  
V Petrishchev ◽  
I V Adamovich ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Nanosecond Pulse ◽  
Temperature Measurements ◽  
Time Resolved
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