Solar Energy Sources

Abstract

The energy content of the sun is considered, and mechanisms for the dissipation and emission of the various kinds of energy are examined. The most important energy flux is the radiant flux originating from nuclear reactions in the solar interior. In the outermost 10⁵ km of the solar body this flux is transported convectively. On top of the convective layer, a region of about 600 km thick constituting the photosphere and low chromosphere is in near-radiative equilibrium. The structure of the chromosphere and corona is mainly due to a mechanical energy flux emanating from the outer convective region. The various transient solar phenomena, which for a part involve high energy processes in magnetic regions, demand thermodynamic upgrading of energy, which, in general terms, can only occur in a motion field with locally a non-zero curl, i.e. solar differential rotation or convection. It is shown that the secular decrease of solar rotational energy can be due to the emission of transformed rotational energy by flares. It is suggested that this happens through the intermediary of differential rotation, which in turns originates by coupling of the solar rotation with convection (see Figure 1).