Fr.: couronne K
The inner part of the → solar corona which extends to about two solar radii. It is due to the → Thomson scattering of light from the → photosphere by the free electrons in the corona. The K corona exhibits a → linearly polarized continuous spectrum. The high speeds of the scattering electrons (on the average 10,000 km s-1 for a temperature of 2 million K) smear out the → Fraunhofer lines except the → H and K lines.