Nuclear line spectroscopy of the 1981 April 27 solar flare

Abstract

The intensities, line centers, and widths of the 13 strongest narrow lines appearing in the observed count spectrum of April 27, 1981 solar flare are determined. It is found that the gamma-ray continuum underlying the narrow lines cannot be modeled solely with a power law, and must be modeled with more structure than simple shapes can provide. While the narrow-line centers are well-determined, both the line intensities and the line widths can vary considerably as the underlying continuum model is changed. Using a 'nuclear continuum' model based on theoretical considerations which provides a good fit to the data, it is found that, while the emission attributed to nuclear interaction and that attributed to electron interactions varied considerably as the flare progressed, the ratio of these two emissions was consistent with a constant value of 1.94 + or - 0.39 throughout the flare.