Comment to "Thomson rings in a disk"
  We have found that the minimum energy configuration of $N=395$ charges confined in a disk and interacting via the Coulomb potential, reported by Cerkaski et al. in Ref.~\cite{Cerkaski15} is not a global minimum of the total electrostatic energy. We have identified a large number of configurations with lower energy, where defects are present close to the center of the disk; thus, the formation of a hexagonal core and valence circular rings for the centered configurations, predicted by the model of Ref.~\cite{Cerkaski15}, is not supported by numerical evidence and the configurations obtained with this model cannot be used as a guide for the numerical calculations, as claimed by the authors. 
Paolo Amore
physics.comp-ph cond-mat.soft