Vortex waves on a nuclear surface

In heavy-ion collisions a localized stable or long lived excitation might develop. The existence of a fairly well defined nuclear surface makes it possible to discuss localized excitations in the nuclear surface region. In the framework of semiclassical nonlinear nuclear hydrodynamics we have presented a type of vortical excitation that are new in nuclear physics. We have found a class of uniformly rotating solutions to nonlinear Euler-type equations on a sphere. The equations of motion describing a localized vortex on a spherical nuclear surface - a bounded region of constant vorticity, surrounded by irrotational flux - are derived. The qualitative analysis of the main properties of this vortex is presented. These excitations may be linked with hot spots created in peripheral heavy-ion collisions. (author). Letter-to-the-editor