  The nature of E1 low-energy strength (LES), often denoted as a "pygmy dipole
resonance", is analyzed within the random-phase-approximation (RPA) in
$^{208}$Pb using Skyrme forces in fully self-consistent manner. A first
overview is given by the strength functions for the dipole, compressional and
toroidal operators. More detailed insight is gained by averaged transition
densities and currents where the latter provide very illustrative flow pattern.
The analysis reveals clear isoscalar toroidal flow in the low-energy bin
6.0-8.8 MeV of the LES and a mixed isoscalar/isovector toroidal/compression
flow in the higher bin 8.8-10.5 MeV. Thus the modes covered by LES embrace both
vortical and irrotational motion. The simple collective picture of the LES as a
"pygmy" mode (oscillations of the neutron excess against the nuclear core) is
not confirmed.
