The size distribution of magnetic bright points derived from Hinode/SOT observations
Möstl, C.; Veronig, A.; Utz, D.; Hanslmeier, A.; Muller, R.; Muthsam, H.
Austria, France
Abstract
Context: Magnetic bright points (MBPs) are small-scale magnetic features in the solar photosphere. They may be a possible source of coronal heating by rapid footpoint motions that cause magnetohydrodynamical waves. The number and size distribution are of vital importance in estimating the small scale-magnetic-field energy.
Aims: The size distribution of MBPs is derived for G-band images acquired by the Hinode/SOT instrument.
Methods: For identification purposes, a new automated segmentation and identification algorithm was developed.
Results: For a sampling of 0.108 arcsec/pixel, we derived a mean diameter of (218 ± 48) km for the MBPs. For the full resolved data set with a sampling of 0.054 arcsec/pixel, the size distribution shifted to a mean diameter of (166 ± 31) km. The determined diameters are consistent with earlier published values. The shift is most probably due to the different spatial sampling.
Conclusions: We conclude that the smallest magnetic elements in the solar photosphere cannot yet be resolved by G-band observations. The influence of discretisation effects (sampling) has also not yet been investigated sufficiently.