What Gamma-Ray Deexcitation Lines Reveal about Solar Flares

Gamma-ray emission from solar flares reveals information about the nature of the accelerated particles and about the physical conditions of the medium through which the accelerated particles are transported. In this paper, we present the gamma-ray line production and loop transport models used in our calculations of highenergy emission. We discuss the calculated interaction time history, the depth distribution, the interacting-particle angular distribution, and fluence ratios of the narrow gamma-ray lines. We show the relationship between the γray observables and the parameters of the transport and line-production models. For illustration, we use calculations of 4.44 MeV C nuclear deexcitation line production. Applications of the calculations to flare observations by both SMM and RHESSI are also presented.