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Title: Passive Measurement of Hydrogen Ground State Rotational and Vibrational Temperatures in Kinetic Plasmas

Abstract

A dipole-quadrupole electron-impact excitation model, consistent with molecular symmetry rules, is presented to fit ro-vibronic spectra of the hydrogen Fulcher-α Q-branch line emissions for passively measuring the rotational temperature of hydrogen neutral molecules in kinetic plasmas with the coronal equilibrium approximation. A quasi-rotational temperature and quadrupole contribution factor are adjustable parameters in the model. Quadrupole excitation is possible due to a violation of the 1st Born approximation for low to medium energy electrons (up to several hundred eV). The Born-Oppenheimer and Franck-Condon approximations are implicitly shown to hold. A quadrupole contribution of 10% is shown to fit experimental data at several temperatures from different experiments with electron energies from several to 100 eV. A convenient chart is produced to graphically determine the vibrational temperature of the hydrogen molecules from diagonal band intensities, if the ground state distribution is Boltzmann. Hydrogen vibrational modes are long-lived, surviving up to thousands of wall collisions, consistent with multiple other molecular dynamics computational results. The importance of inter-molecular collisions during a plasma pulse are also discussed.

Authors:
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
988887
Report Number(s):
PPPL-4548
TRN: US1007027
DOE Contract Number:  
DE-AC02-09CH11466
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; APPROXIMATIONS; BORN APPROXIMATION; DISTRIBUTION; ELECTRONS; EXCITATION; GROUND STATES; HYDROGEN; KINETICS; PLASMA; QUADRUPOLES; SPECTRA; SYMMETRY; Hydrogen, Diagnostics, Optical Spectroscopy

Citation Formats

D.R. Farley, D.P. Ludberg and S.A. Cohen. Passive Measurement of Hydrogen Ground State Rotational and Vibrational Temperatures in Kinetic Plasmas. United States: N. p., 2010. Web. doi:10.2172/988887.
D.R. Farley, D.P. Ludberg and S.A. Cohen. Passive Measurement of Hydrogen Ground State Rotational and Vibrational Temperatures in Kinetic Plasmas. United States. https://doi.org/10.2172/988887
D.R. Farley, D.P. Ludberg and S.A. Cohen. 2010. "Passive Measurement of Hydrogen Ground State Rotational and Vibrational Temperatures in Kinetic Plasmas". United States. https://doi.org/10.2172/988887. https://www.osti.gov/servlets/purl/988887.
@article{osti_988887,
title = {Passive Measurement of Hydrogen Ground State Rotational and Vibrational Temperatures in Kinetic Plasmas},
author = {D.R. Farley, D.P. Ludberg and S.A. Cohen},
abstractNote = {A dipole-quadrupole electron-impact excitation model, consistent with molecular symmetry rules, is presented to fit ro-vibronic spectra of the hydrogen Fulcher-α Q-branch line emissions for passively measuring the rotational temperature of hydrogen neutral molecules in kinetic plasmas with the coronal equilibrium approximation. A quasi-rotational temperature and quadrupole contribution factor are adjustable parameters in the model. Quadrupole excitation is possible due to a violation of the 1st Born approximation for low to medium energy electrons (up to several hundred eV). The Born-Oppenheimer and Franck-Condon approximations are implicitly shown to hold. A quadrupole contribution of 10% is shown to fit experimental data at several temperatures from different experiments with electron energies from several to 100 eV. A convenient chart is produced to graphically determine the vibrational temperature of the hydrogen molecules from diagonal band intensities, if the ground state distribution is Boltzmann. Hydrogen vibrational modes are long-lived, surviving up to thousands of wall collisions, consistent with multiple other molecular dynamics computational results. The importance of inter-molecular collisions during a plasma pulse are also discussed.},
doi = {10.2172/988887},
url = {https://www.osti.gov/biblio/988887}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Sep 21 00:00:00 EDT 2010},
month = {Tue Sep 21 00:00:00 EDT 2010}
}