General Treatment of Vortical, Toroidal, and Compression Modes

Abstract

The multipole vortical, toroidal, and compression modes are analyzed. Following the vorticity concept of Ravenhall and Wambach, the vortical operator is derived and related in a simple way to the toroidal and compression operators. The strength functions and velocity fields of the modes are analyzed in $^{208}$Pb within the random-phase-approximation using the Skyrme force SLy6. Both convection and magnetization nuclear currents are taken into account. It is shown that the isoscalar (isovector) vortical and toroidal modes are dominated by the convection (magnetization) nuclear current while the compression mode is fully convective. The relation between the above concept of the vorticity to the hydrodynamical vorticity is briefly discussed.Comment: 15 pages, 9 figures, to be published in Phys. Rev. C. This is the replacement of 1105.0837[nucl-th]. The text was essentially reshuffled following the request of the PRC referee. A scale of strength functions in Figs. 1-5 was corrected. The corrections do not change main result