  Electron hydrodynamics is currently known to emerge only when
electron-electron interaction dominates over the momentum-nonconserving
scatterings of electrons, where the electron transport is described by a
hydrodynamic equation. Here we show that electron transport in electron systems
with the spin Hall effect is also given by the hydrodynamic equation, whose
kinetic viscosity is determined by the spin diffusion length and the transport
lifetime. The electric current vorticity is proportional to the spin
accumulation due to the spin Hall effect in two-dimensional systems. We
demonstrate by solving the hydrodynamic equation in a two-dimensional system
with a cavity, combined with micromagnetic simulation for an attached chiral
magnetic insulator, that the spin accumulated near the boundary of the cavity
creates a magnetic skyrmion. Our findings and demonstration shed light on a
novel aspect of electron hydrodynamics and spin transport.
