The phrase "solar chromosphere" refers to a layer of the Sun's atmosphere that is located just above the surface. It is a region where temperatures increase, and it appears as a reddish color during a total solar eclipse. Full definition
Scientists with experience in treatment of astrophysical partially ionized plasmas (interstellar medium, solar chromosphere, Earth's ionosphere) are encouraged to apply. (uksolphys.org)
First he applied it to the solar chromosphere, then to stellar spectra. (en.wikipedia.org)
Observations at shorter wavelengths probe deeper into the solar chromosphere than longer wavelengths. (public.nrao.edu)