Passive Measurement of Hydrogen Ground State Rotational and Vibrational Temperatures in Kinetic Plasmas | |
Farley, D. R. ; Ludberg, D. P. ; Cohen, S. A. | |
Princeton University. Plasma Physics Laboratory. | |
关键词: Approximations; Spectra; Hydrogen, Diagnostics, Optical Spectroscopy; Excitation; 70 Plasma Physics And Fusion Technology; | |
DOI : 10.2172/988887 RP-ID : PPPL-4548 RP-ID : DE-AC02-09CH11466 RP-ID : 988887 |
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美国|英语 | |
来源: UNT Digital Library | |
【 摘 要 】
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.
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