chromosphere
The chromosphere is a layer of the Sun's atmosphere located above the photosphere and below the corona. It is characterized by a reddish glow as seen during solar eclipses and is the region where solar filaments and prominences are observed.
Source: eclipse2017.nasa.gov
APODs including "chromosphere"
Blue Sun Bursting
20/05/2013
Our Sun is not a giant blueberry. Our Sun can be made to appear similar to the diminutive fruit, however, by imaging it in a specific color of extreme violet light called CaK that is emitted by the very slight abundance of ionized Calcium in the Sun's atmosphere, and then false color-inverting the image. This solar depiction is actually scientifically illuminating as a level of the Sun's chromosphere appears quite prominent, showing a crackly textured surface, cool sunspots appearing distinctly bright, and surrounding hot active regions appearing distinctly dark. The Sun is currently near the maximum activity level in its 11 year cycle, and has emitted powerful flares over the past week. During times of high activity, streams of energetic particles from Sun may impact the Earth's magnetosphere and set off spectacular auroras.