English: The electric field of an electromagnetic wave is shown, polarized in the plane of the monitor. Coming from a plane-wave source at the bottom of a metallic waveguide, the wave impinges a metallic obstacle, and diffracts on its edge.

The edge was chosen to be sharp. Notice the interaction with the metal tip generates weak surface plasmons, relatively slowly propagating along the obstacle.

This animation was generated by the python-meep-utils project (https://github.com/FilipDominec/python-meep-utils), using the open-source Maxwell solver, MEEP.