The structure, energy balance, and winds of cool stars

Solar magnetic field phenomena which occur in cool stars are summarized. Factors which can produce magnetic fields in stars are listed. Information on cool star atmospheres, provided by high dispersion spectra, is discussed. These spectra show that in Beta Dra (G2 Ib) the transition lines are red shifted (an antiwind), perhaps indicating downflows in closed magnetic flux tubes, as seen in the solar flux tubes above sunspots. The G and K giants and supergiants are classed as active, quiet, or hybrid, depending on whether their atmospheres are dominated by closed magnetic flux tubes, open field geometries, or a predominantly open geometry with a few closed flux tubes embedded.