Abstract
Magnetic skyrmions are smooth topological textures of the magnetization that are localized within a two-dimensional plane. They arise in magnetic systems that lack inversion symmetry where they are stabilized by the Dzyaloshinskii-Moriya interaction. In bulk materials, magnetic skyrmions extend in the third direction forming an effective string. Such skyrmion strings either arise as excitations or they condense and form a crystal. These strings can be dynamically excited resulting in various vibrational modes. We provide an overview of the dynamics of skrymion strings [1], that can be found in chiral magnets like MnSi or FeGe, and we compare theoretical predictions with magnetic resonance spectroscopy [2], spin-wave
spectroscopy [3], inelastic neutron scattering [4] and Brillouin light scattering [5]. At high energies, the spin-wave dynamics is governed by an emergent orbital magnetic field that is directly linked to the topological density of the skyrmions. As a result, magnon Landau levels emerge in skyrmion crystals. At low-energies the dynamics is determined by an effective elasticity theory of the strings, and we show that a single string supports non-linear solitary waves [6] similar to vortex filaments in fluids.