Stimulated amplification in an astrophysical plasma: An FeII space laser in gas condensation in the vicinity of eta carinae
We consider the conditions necessary for the development of an inverted population among the energy levels of free atoms in a medium exposed to radiation in spectral nonequilibrium. In particular, we focus on monochromatic radiation occurring as a result of an accidental wavelength coincidence between a pumping emission line and a pumped absorption line in two different elements. We examine especi