Chromosphere 色球
The chromosphere (literally, "sphere of color") is the second of the three main layers in the Sun's atmosphere and is roughly 2,000 kilometers deep. It sits just above the photosphere and just below the solar transition region.
The density of the chromosphere is very low being only 10 times that of the photosphere, the layer just below it, and 10 times that of the atmosphere of Earth. This makes the chromosphere normally invisible and it can be seen only during a total eclipse, where its reddish color is revealed. The color hues are anywhere between pink and red.
However, without special equipment, the chromosphere cannot normally be seen due to the overwhelming brightness of the photosphere.