Toroidal resonance: relation to pygmy mode, vortical properties and   anomalous deformation splitting
  We review a recent progress in investigation of the isoscalar toroidal dipole resonance (TDR). A possible relation of the TDR and low-energy dipole strength (also called a pygmy resonance) is analyzed. It is shown that the dipole strength in the pygmy region can by understood as a local manifestation of the collective vortical toroidal motion at the nuclear surface. Application of the TDR as a measure of the nuclear dipole vorticity is discussed. Finally, an anomalous splitting of the TDR in deformed nuclei is scrutinized. 
V.O. Nesterenko, J. Kvasil, A. Repko, W. Kleinig, and P.-G. Reinhard
nucl-th