Describe the structure of the Sun and the physical processes taking place in its various parts.

Core. A thermonuclear reaction takes place in the core of the Sun. The core is surrounded by a radiation zone in which no nuclear reactions take place, and the transfer of energy is carried out mainly due to radiation. This zone is surrounded by a convection zone. Convective flows appear in this zone, providing additional energy transfer. The photosphere is the upper layer of the Sun, which is surrounded by the chromosphere, above which there is a highly rarefied gaseous envelope – the solar corona.