Institution(s): 1. MPI for Solar System Research
Three-dimensional radiative magnetohydrodynamics (3D RMHD) simulations have become an important tool to investigate the near-surface layers (upper part of the convective envelope and photosphere) of the Sun and other stars. I present a grid of 3D RMHD simulations of main-sequence stars with six different spectral types (including the Sun) and different field strengths and geometries. The structure of small-scale magnetic flux concentrations is analysed and their relevance for stellar spectroscopy and spectropolarimetry as well as for solar and stellar irradiance modelling is discussed. First attempts to simulate starspots are also addressed.