The Sun at small scales

摘要

The Sun is a unique laboratory for studying particular astrophysical processes, such as the interaction of thermal convection with a magnetic field. But many important phenomena in the solar atmosphere are thought to occur on length scales smaller than the resolution limit of current solar telescopes (about 0.2 arcsec-onds, or 140 km). Hence the quest for higher resolution, and hence a workshop on the topic. The energy generated by nuclear fusion in the Sun's core is transported outward first by radiation, and then through the outermost layers by thermal convection. The Sun's magnetic field, generated by a dynamo mechanism at the base of the convective zone, is transported to the surface by diffusion and buoyancy. Near the surface the turbulent convection and the magnetic field interact as a complicated nonlinear system. This interaction produces fine-scale structuring of the magnetic field, which in turn dominates nearly all aspects of solar activity, including coronal heating, flares and mass ejections, and radio, X-ray and γ-ray emission.