The emission-line spectrum from a slab of hydrogen at moderate to high densities

Abstract

The paper presents computation of line intensities for the hydrogen emission from a static slab at moderate to high electron densities. Results are given for the line intensities of L(alpha), H(alpha) through H8, P(alpha) to P(gamma), and B(alpha) to B(gamma); the fractional hydrogen ionization, the slab thickness, and the departure coefficients were tabulated for levels up to n = 20. An escape probability treatment of the radiative transfer was adopted to allow for optical depth effects in the Balmer and higher series of lines; the conditions which produce very steep Balmer decrements are large optical depths in H(alpha), low photoionization rates, and electron densities between 10 to the 8th power and 10 to the 12th power per cu cm.