The very hot outer layer of the Sun's atmosphere, composed of highly diffused, superheated, ionized gases, and extending into interplanetary space. Some of the hot gasses in the solar corona escape the Sun to form the solar wind
Space Science Institute (SSI),Space Weather Center, Glossary of Space Weather-Related Terms, Colorado, USA 2011. http://www.spaceweathercenter.org/glossary/001/01. html, (Space Wthr - Amer) {860}