A unified treatment of the relaxation phenomenon in radiating argon plasma flows.

Bershader, D.; Oettinger, P. E.

doi:10.2514/3.4260

Cited by 40 publications

(12 citation statements)

References 13 publications

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“…In particular, they noted that the excited-state populations directly behind the shock did not agree with predictions based on the currently accepted theory. Specifically they did not satisfy the modified Saha equation used in earlier work by Oettinger & Bershader (1967). However, since both non-metastable and metastable populations behaved in a similar way for both stable and unstable shock waves, no correlation with the Anomalous Relaxation Theory was found.…”

Section: Introductionmentioning

confidence: 75%

Relaxation behind shock waves in ionizing neon

et al. 1991

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Experiments in ionizing neon are described in which heavy-particle and electron densities are measured and compared with the current kinetic model. The experimental results allow a determination of the atom-atom collisional excitation cross-section constant, giving a value of (8±2) × 10−20 cm2/eV for the range of conditions examined. The population of two of the excited-state levels of the atom are measured and compared with theoretical predictions. The experimental populations are found to follow the expected behaviour in the quasi-equilibrium region, but are several orders of magnitude higher than predicted in the nonequilibrium zone. These findings suggest that the depopulation of excited states through ionizing collisions occurs more slowly than expected. Absorption linewidths and line shifts are also measured in the quasi-equilibrium region and found to compare well with theory. A small precurson population is also observed and population measurements in this region are compared with other experimental results in argon and krypton.

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Section: Introductionmentioning

confidence: 75%

Relaxation behind shock waves in ionizing neon

et al. 1991

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“…As for the computation, since the grid in the nozzle region is too coarse to allow accurate estimation of the velocity variation, instead of calculating the thrust American Institute of Aeronautics and Astronautics by integrating the momentum over a given cross sectional surface, it is estimated via Eqs. (18) and (19) Values for the thrust and the energy conversion efficiency from the experiment and the computation are listed in Table 1. The mass flow rates were the same.…”

Section: 4 Energy Conversion Efficiencymentioning

confidence: 99%

Simulation of a 2-kW class laser thruster

Molina-Morales¹,

Toyoda²,

Komurasaki³

et al. 2001

39th Aerospace Sciences Meeting and Exhibit

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Laser propulsion powered by a CW laser has been studied. Thruster performance and energy balance in the thruster were numerically computed. Laser beam optics, inverse-bremsstrahlung absorption, ionization/recombination reactions, radiation, heat conduction, and convection have been modeled. Computational stiffness due to the very small flow speed has been overcome by using a Flux Vector Splitting implicit scheme with a large CFL number. The computed positions of the Laser Sustained Plasma (LSP) in the thruster show good agreement with the measured ones. The estimated energy conversion efficiency was 23%, and the rest of the input power was lost as radiation from the LSP and also carried by the laser beam passing through the LSP.

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“…Continuum radiation and line radiation in argon have been studied by Oettinger and Bershader [1967] and Kozlov [1974] respectively. Both analyses rely on approximate corrections, known as gaunt factors, to the classical radiation expressions for quantum mechanical effects.…”

Section: Lsp Lossesmentioning

confidence: 99%

Nonlocal thermodynamic equilibrium in laser-sustained plasmas

Zerkle

Krier

1994

AIAA Journal

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Ia. REPORT SECURITY CLASSIFICATION lb. RESTRICTIVE MARKINGS Unclassified None 2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION IAVAILABIUTY OF REPORT Approved for public release; 2b. DECLASSIFICATION/DOWNGRADING SCHEDULE distribution is unlimited 4. PERFORMING ORGANIZATION REPORT NUMBER(S) S. MONITORING ORGANIZATION REPORT NUMBER(S) UILU ENG 92-4016 AFOSR-TR 6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION

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A unified treatment of the relaxation phenomenon in radiating argon plasma flows.

Cited by 40 publications

References 13 publications

Relaxation behind shock waves in ionizing neon

Relaxation behind shock waves in ionizing neon

Simulation of a 2-kW class laser thruster

Nonlocal thermodynamic equilibrium in laser-sustained plasmas

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