  This work studies the resonance excitations of the three-dimensional
skyrmions lattice in the finite thickness plate of an isotropic chiral magnet
using spin dynamics simulations. We found that the absorption spectra and
resonance modes differ from those predicted by the two-dimensional model and
the model of the unconfined bulk crystal. The features observed on the spectra
can be explained by the formation of chiral standing spin waves, which,
contrary to conventional standing spin waves, are characterized by the helical
profile of dynamic magnetization of fixed chirality defined by the
Dzyaloshinskii-Moriya interaction. In this case, the dynamic susceptibility
becomes a function of the plate thickness, which gives rise to an interesting
effect that manifests itself in periodical fading of the intensity of
corresponding modes and makes excitation of these modes impossible at specific
thicknesses.
