Fusion Science and Technology / Volume 5 / Number 1 / January 1984 / Pages 5-16
Technical Paper / Special Section Contents / ICF Chamber Engineering / dx.doi.org/10.13182/FST84-A23073
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The frequency dependence of a thermal radiation field complicates the computation of radiative energy transport in optically thin media because the spectrum may be uncoupled from local thermodynamic conditions. A model for combining the effect of the frequency dependence into a radiation temperature chosen to represent the temperature of both local and nonlocal emitting regions is described. The derived equations are much easier to solve than the frequency-dependent equations and can be applied to a broad class of problems. The equations are used to investigate the response of a gas in an inertial confinement fusion (ICF) reaction chamber to target explosions. The response is compared for ambient densities of 1.77 × 1018 and 1.77 × 1017 atom/cm3. The error in using the brightness temperature instead of a color temperature to evaluate the opacities is illustrated. An analytic analysis shows the cooling wave observed from energy releases > 1018 erg will not occur in an ICF cavity. This is confirmed by the numerical calculations.