Energy balance and stability

Recent theoretical work pertaining to the energy balance and stability of stellar coronae is reviewed. While in magnetically confined coronal regions coronal heating balances only the radiation losses of the corona and transition region, open regions can also lose energy by means of stellar wind and outward thermal conduction. The relative importance of these kinds of energy losses, and the asymptotic properties of the stellar wind, depend sensitively on the radial distribution of the energy input. Solar coronal models, both for open and closed regions, can often be applied to other stars. The requirements for which this is possible are briefly discussed. Stability analyses that are not restricted to the corona alone, but rather include the transition region and upper chromosphere, are important for our understanding of the detailed energy balance of outer stellar atmospheres. The stability of the complete system chromosphere/transition region/corona is probably closely related to the recent observational result that with increasing stellar activity the coronal radiation increases faster than the chromospheric radiation.