Published online by Cambridge University Press: 14 August 2015
The Kitt Peak multi-channel magnetograph was used to make raster scans of the supergranulation at the center of the disk. The scan pattern was arranged to largely cancel out the effects of the 5 min oscillations and the granulation and to enhance visible effects of the supergranulation.
The results show vertical supergranular motions. These motions consist of relatively isolated ‘patches’ of downward flowing material, or ‘downdrafts’, with an average speed of 0.1 km/s. These downdrafts coincide with patches of magnetic field, and the speed of the downdraft is linearly proportional to the magnetic field strength (50 to 100 G). These downdrafts are also regions of increased brightness in the chromosphere and photosphere.