Solar Wind

Supersonic flow of high-speed charged particles continuously blowing off a star (mostly e- and p+). When originating from stars other than the Sun, it is sometimes called a "stellar" wind. The solar wind may be viewed as an extension of the corona into interplanetary space. The solar wind emanates radially from all parts of the Sun: the fast wind originates from the coronal holes and the quiet Sun, whereas the slow wind arises from the coronal streamers. Active regions, which lie under closed magnetic loops, are also a source of the slow wind.

The solar wind contains roughly equal number of electrons and protons, along with a few heavier ions, and blows continuously from the surface of the Sun at an average velocity of ~400 km/s. The Sun’s solar wind leads to a loss of ~10-14 Msun per year. The solar wind is fractionated from the photosphere by the forces that accelerate the ions off of the Sun. This fractionation appears to be ordered by the first ionization potential (FIP) of the elements (low-FIP elements tend to be over-abundant and high-FIP elements tend to be under-abundant).

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