Dispersion of the solar magnetic flux in the undisturbed photosphere as derived from SDO/HMI data

To explore the magnetic flux dispersion in the undisturbed solar photosphere, magnetograms acquired byHelioseismic and Magnetic Imager (HMI) onboard the Solar Dynamic Observatory (SDO) were utilized. Two areas, a coronal hole (CH) area and an area of super-granulation (SG) pattern, were analysed. We explored the displacement and separation spectra and the behaviour of the turbulent diffusion coefficient, K. The displacement and separation spectra are very similar to each other. Small magnetic elements (of size 3-100 squared pixels and the detection threshold of 20 Mx sm-2) in both CH and SG areas disperse in the same way and they are more mobile than the large elements (of size 20-400 squared pixels and the detection threshold of 130 Mx sm-2). The regime of super-diffusivity is found for small elements (γ ≈ 1.3 and K growing from ~100 to ~ 300 km2 s-1). Large elements in the CH area are scanty and show super-diffusion with γ ≈ 1.2 and K = (62-96) km2 s-1 on a rather narrow range of 500-2200 km. Large elements in the SG area demonstrate two ranges of linearity and two diffusivity regimes: sub-diffusivity on scales 900-2500 km with γ = 0.88 and K decreasing from ~130 to ~100 km2 s-1, and super-diffusivity on scales 2500-4800 km with γ ≈ 1.3 and K growing from ~140 to ~200 km2 s-1. A comparison of our results with the previously published shows that there is a tendency of saturation of the diffusion coefficient on large scales, i.e. the turbulent regime of super-diffusivity is gradually replaced by normal diffusion. © 2018 The Author(s).