A display may change colours or pulse in intensity as the ever-changing geomagnetic field is disturbed by the solar wind and additional solar particles stream into the atmosphere. Aurora may appear to hang static in the sky, or they may dance and flutter, or even appear to explode upward along magnetic field lines. Auroral arcs or curtains typically cover large areas of sky. They are usually an evenly curved arc of light with a smooth lower boundary, which may extend from horizon to horizon. Arcs may dance and turn, rippling like a curtain responding to a light breeze.
Auroral bands are similar to arcs but with a folded or uneven lower edge.
Auroral coronae are rayed arcs or bands seen from below so that the light appears as sunbeams spraying out in all directions. Auroral patches are small areas of light that look like a cloud in the night sky. Often they appear to flash or pulse, disappearing and reappearing over a short period of time. Auroral rays are thin beams or shafts of auroral light that hang vertically above the observer. Auroral veils are large featureless clouds of auroral light.