An Ellerman bomb is a small, bright structure, also known as a Severny moustache,
that appears in a solar active region,
most often in an emerging flux region or on the edge of a sunspot
where the magnetic field is breaking through the surface. Ellerman bombs
usually last less than 5 minutes and are best seen it the wings of H-alpha;
they are named after the American astronomer Ferdinand Ellerman (1869–1940).