Large-scale brightness inhomogeneities in the solar atmosphere

The intensity residuals are analyzed from a series of solar limb-darkening measurements in the wavelength range 5656 to 2997 Å. The lengths of residual strings of the same sign exceed expectation by several orders of magnitude. The power spectrum of the residuals shows a weak excess around 6000 km. For further study the 34 000 limb-darkening residuals are subdivided into 5100 bright and faint cells. The frequency distribution of cell sizes peaks around 4500 km and increases from center to limb, the faint cells showing the greater center-limb effect. The cells are also studied as to contrast. A synoptic view indicates that only 12% of the cells are identifiable after a half hour. Phenomena that may combine to produce the observed wide spectrum of brightness inhomogeneities are briefly discussed.