Multiple vortex-antivortex pair generation in magnetic nanodots

The interaction of a magnetic vortex with a rotating magnetic field causes the nucleation of a vortexantivortex pair leading to a vortex polarity switching. The key point of this process is the creation of a dip, which can be interpreted as a nonlinear resonance in the system of certain magnon modes with nonlinear coupling. The usually observed single-dip structure is a particular case of a multidip structure. The dynamics of the structure with n dips is described as the dynamics of nonlinearly coupled modes with azimuthal numbers m=0, n , 2n. The multidip structure with arbitrary number of vortex-antivortex pairs can be obtained in vortex-state nanodisk using a spaceand a time-varying magnetic fields. A scheme of a possible experimental setup for multidip structure generation is proposed.