The continuum radiation of oxygen and nitrogen for use in plasma temperature determination

Morris, J.; Krey, R. U.; Bach, G.

doi:10.1016/0022-4073(66)90017-3

Cited by 35 publications

(3 citation statements)

References 11 publications

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“…However, the comparison of predictions with actual measurements [104][105][106][107][108] is much worse, with the agreement ranging from 30-50%. A complication in the analyses of the measurements is the possible influence of the negative nitrogen ion, which provides an increase in the continuum radiation.…”

Section: Atomic Photoionization Cross Sections For Airmentioning

confidence: 99%

Assessment of Radiative Heating Uncertainty for Hyperbolic Earth Entry

Johnston

Mazaheri

Gnoffo

et al. 2011

42nd AIAA Thermophysics Conference

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This paper investigates the shock-layer radiative heating uncertainty for hyperbolic Earth entry, with the main focus being a Mars return. In Part I of this work, a baseline simulation approach involving the LAURA Navier-Stokes code with coupled ablation and radiation is presented, with the HARA radiation code being used for the radiation predictions. Flight cases representative of peak-heating Mars or asteroid return are defined and the strong influence of coupled ablation and radiation on their aerothermodynamic environments are shown. Structural uncertainties inherent in the baseline simulations are identified, with turbulence modeling, precursor absorption, grid convergence, and radiation transport uncertainties combining for a +34% and −24% structural uncertainty on the radiative heating. A parametric uncertainty analysis, which assumes interval uncertainties, is presented. This analysis accounts for uncertainties in the radiation models as well as heat of formation uncertainties in the flowfield model. Discussions and references are provided to support the uncertainty range chosen for each parameter. A parametric uncertainty of +47.3% and −28.3% is computed for the stagnation-point radiative heating for the 15 km/s Mars-return case. A breakdown of the largest individual uncertainty contributors is presented, which includes C3 Swings cross-section, photoionization edge shift, and Opacity Project atomic lines. Combining the structural and parametric uncertainty components results in a total uncertainty of +81.3% and −52.3% for the Mars-return case.In Part II, the computational technique and uncertainty analysis presented in Part I are applied to 1960s era shock-tube and constricted-arc experimental cases. It is shown that experiments contain shock layer temperatures and radiative flux values relevant to the Mars-return cases of present interest. Comparisons between the predictions and measurements, accounting for the uncertainty in both, are made for a range of experiments. A measure of comparison quality is defined, which consists of the percent overlap of the predicted uncertainty bar with the corresponding measurement uncertainty bar.

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Section: Atomic Photoionization Cross Sections For Airmentioning

confidence: 99%

Assessment of Radiative Heating Uncertainty for Hyperbolic Earth Entry

Johnston

Mazaheri

Gnoffo

et al. 2011

42nd AIAA Thermophysics Conference

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“…Malheureusement on ne connaît pas de valeurs théoriques des sections efficaces 0,"; de l'ion négatif dont l'existence a fait I'objet de très nombreuses controverses [13], [14], [16], [18], [20], [30], les calculs théoriques sur cet ion [31] et [32] donnant des valeurs de o N -pour l'état fondamental 3P en désaccord avec les résultats expérimen-taux. Il semblerait cependant que les états pouvant contribuer à l'émission sont les états 3P (fondamental) et/ou le premier état excité ID.…”

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CONTRIBUTION DE L'ION N^- A L'ÉMISSION CONTINUE D'UN PLASMA D'AZOTE A 4 955 Å

Fauchais¹,

Baronnet²,

Bayard³

et al. 1973

J. Phys. Colloques

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Résumé. -Dans un plasma d'azote à la pression atmosphérique l'intensité du fond continu, mesurée dans le visible, est su~érieure à la somme des contributions que l'on peut évaluer pour le bremsstrahlung et les recombinaisons électrons-ions. Les mesures que nous avons effectuées à 4 955 A, région où le fond continu est particulièrement bien défini (absence de spectres molé-culaires ou atomiques), semblent montrer qu'entre 8 000 et 14 000 K la prise en compte de la contribution de l'ion N-permet, dans l'hypothèse de I'ETL, de déduire de l'enregistrement du fond continu des températures comparables à celles obtenues à partir des spectres atomiques et molé-culaires.Abstract. -In a nitrogen plasma at atmospheric pressure the continuum radiation measured in the visible is higher than the contributions from positive ions. The measurements we have done at 4 955 A, region where the continuum is perfectly well defined (no atomic or molecular spectra in the neighbourhood), seems to show that between 8 000 and 14 000 K we have to consider the contribution of negative ion N-which permits, in the LTE, to deduce, from the continuum measurements, temperatures similar to those we get from atomic and molecular spectra.

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“…Indications are that continuum ultraviolet should be significant down to about 800Ä (Refs. 81,82,83,84,85,86) in the gases and temperatures of current interest. Calculations of…”

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confidence: 99%