A thick gas model near boundaries.

B = radiosity of wall Eb = emissive power of blackbody En = integroexponential function of order n G = incident radiation 7,/~ = half-range intensities k = thermal conductivity L = distance between plates

penetration depth of wall effect e = emissivity of wall 6 — dimensionless absolute temperature, T/T* fj, = dummy variable p — reflectivity of wall optical depth in absorbing layer, ay