  Chiral magnetic interactions induce complex spin textures including helical
and conical spin waves, as well as particle-like objects such as magnetic
skyrmions and merons. These spin textures are the basis for innovative device
paradigms and give rise to exotic topological phenomena, thus being of interest
for both applied and fundamental sciences. Present key questions address the
dynamics of the spin system and emergent topological defects. Here we analyze
the micromagnetic dynamics in the helimagnetic phase of FeGe. By combining
magnetic force microscopy, single-spin magnetometry, and
Landau-Lifschitz-Gilbert simulations we show that the nanoscale dynamics are
governed by the depinning and subsequent motion of magnetic edge dislocations.
The motion of these topologically stable objects triggers perturbations that
can propagate over mesoscopic length scales. The observation of stochastic
instabilities in the micromagnetic structure provides new insight to the
spatio-temporal dynamics of itinerant helimagnets and topological defects, and
discloses novel challenges regarding their technological usage.
