  We systematically investigate the properties of bulk, surface and edge
plasmons in Weyl semimetals in presence of a magnetic field. It is found that
unidirectional plasmons with different properties exist on different surfaces,
which is in consistent with the nontrivial topology of the three-dimensional
(3D) bulk plasmons. These novel plasmons possess momentum-location lock and may
travel between surfaces. The anomalous Hall conductivity brings about abundant
anisotropic plasmon dispersions, from linear to parabolic or even hyperbolic
bands. With the help of a semiclassical picture for the formation of the Weyl
orbits, we point out the Fermi-arc plasmons at opposite surfaces can make up
another unique 3D topological plasmon. Furthermore, there is a gapless
unidirectional edge plasmon protected by the topology whose direction and
position can be controlled by external field. Our work thus uncovers
topological features of Weyl plasmons, which may have important applications in
photoelectric devices based on chiral/topological plasmonics.
