Brightness and size of small-scale solar magnetic flux concentrations

The new 1 m Swedish Solar Telescope SST on La Palma allows to observe inter-granular G -band bright points (igBP) in solar active regions at an unprecedented spatial resolution. The igBP are reasonably assumed to be small-scale magnetic flux-concentrations. A sample of more than 1500 igBP shows tight relations of diameter and brightness in the G -band and in the continuum; it covers a diameter range of 100 km to 300 km, with a most frequent value near 160 km. Features larger than 300 km formerly reported, evidently result from insufficient spatial resolution; that upper diameter limit is close to the typical width of inter-granular lanes, and suggests a “gap” to small pores. The lack of igBP with sizes below 130 km is discussed not to arise from the finite spatial resolution of the 1 m telescope.

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