Photosphere and corona represent two of the four outlayers of the Sun. Photosphere represents the deepest layer of the Sun, while corona represents the outmost layer of the Sun. Photosphere can be seen straight, while corona cannot be directly observed, although, during eclipse, it can be seen. Corona can also be observed using a device called coronagraph. Photosphere has an upper and a lower limit, while corona is bounded by lower limit only. Temperature in corona varies between 500,000K and millions of K, while temperature in photosphere varies between 3700 C at the top and 6200 C at the bootom.
Solar prominence or filaments connects photosphere and corona. Solar proeminence. A stable proeminence can last in corona for several months. The instability of structure of solar proeminence can cause eruptions, when plasma is released. The structure of the material released in eruption is magnetic and if interactions with Earth's magnetic field happen, then communication netweorks and electrical power networks can be damaged.