The Solar spots - are the dark formations on the Sun's disk. The dimensious of spots may be different from the small with the diameter of 1000 - 2000 km to the giant many times more than our planet. The greatest observed spot is 100 thousand kilomiters. The spots are the places of the magnetic fields' getting out to the solar atmosphere. The spots are colder than the surrounding substance nearly 1500 K and consequently are less bright. That's why they look so dark
Practically always the spots are surrounded by the light fields, called torches. The torches are hotter than surrounding atmosphere in 2000 K and have a complicated structure.
The Solar corona - is an external part of the Solar atmosphere, it contains from the hot (1 -2 ml K) rarefied plasma with high-ionization. It is followed to the distance of several tens of the Sun radius and then is slowly scattering in interplanet space.
Protuberances (from the Latin protubero - to swell) - are the giant plasma formations up to 100 thousand kilomiters long, with high density and lower temperature than the surrounding them corona plasma. On the Sun's disk they seen as the dark fibre or the archs and jets.
The Solar convection zone is the layer with the thickness of 150 - 200 thousand kilomiters, situated under the photosphere; the substance of this layer being in convectional movement transformes the energy from inside the Sun's to its surface.
Radiant balance in the stars is a balanced condition of a star layer where the energy is carried only by irradiation (see item "the radiant carrying"). The radiant balance is violated in the star convective zone, where energy is transformed by convection and inside the white dwarfs with the proper thermal conditivity of degenerate electron gas.
Chromosphere (from chromo... and sphere) is a layer of the solar atmosphere between photosphere and corona with a thickness of 7 - 8 thousand kilomitres. During the whole solar eclipses it is observed as a bright ring around the Sun. The great non uniformaty of temperature (5 - 10 thousand K), density and other parametres; the structures elements are network and spicules.