Model for the relationship of granulation and supergranulation

Abstract

In this report a mechanism is proposed for producing the observed solar supergranulation from the photospheric granulation by a dissipative decay of two-dimensional turbulence, which leads to concentration of the energy spectrum to the longest wavelengths. This concentration of convective eddies by selective dissipation to the scale with the maximum available spatial dimension and with a much longer time scale is verified by mode-mode coupling seen in computer simulations as well as in laboratory experiments. Theoretical predictions for these granulation scales and magnetic structures can be tested by high quality observations of the solar surface.