Organization scale of photospheric magnetic imbalance in coronal holes

Abstract

Abstract To investigate the statistical properties of the photospheric magnetic fields underlying coronal holes (CHs) and “normal” coronal regions a classical technique, the signed measure, is used. This technique allows to characterize the scaling behavior and the topology of sign-oscillating magnetic structures in selected regions of line of sigth (LoS) magnetograms recorded by the Heliosismic Magnetic Imager on board of the Solar Dynamic Observatory (SDO/HMI). To this end we have compared the properties of the photospheric magnetic field underlying 60 CHs and 60 non-coronal holes (NCHs). In particular, in addition to having studied distributions and momenta of photospheric magnetic fields associated to the selected regions, we have performed the sign singularity analysis computing the cancellation functions of the highly fluctuating photospheric magnetic fields. We have found that photospheric magnetic fields associated to CHs are imbalanced in the sign and that this imbalance emerges mainly at the supergranular scales.