Velocity Fields in the Solar Atmosphere. III. Large-Scale Motions, the Chromospheric Network, and Magnetic Fields.
Results of a detailed study of large-scale cellular motions in the solar photosphere are presented. The velocity cells (called "supergranules") are of various sizes and shapes and have an average diameter of 32000 km and a 20-hour lifetime; the motion within each cell is mainly horizontal, proceeding from the center toward the outer boundary with a velocity of 0.3-0.5 km/sec. A strong spatial correspondence is found between the cell boundaries and several other features: (1) the chromospheric Ca+ X 3934 network; (2) the network of descending matter (1.0-2.0 km/sec) observed in Ha and Hp; and (3) the magnetic field pattern. The characteristics of the velocity cells suggest that they are non-stationary convection currents originating perhaps at a quite deep level inside the convective envelope. These observations, together with the theoretical predictions of Parker (1963a, b) and Osterbrock (1961), suggest an explanation for the origin of the chromospheric network seen in Ca+ and in the Balmer lines