Diffuse Aurora
Definition
A faint, structureless auroral glow spread across the sky, without distinct curtains or rays.
In plain language
Not every aurora is a dancing curtain โ much of the time the oval glows as a dim, even wash of light that many observers mistake for thin cloud or light pollution.
The science
Diffuse aurora arises from steady, wave-scattered precipitation of plasma sheet electrons, accounting for much of the oval's total energy input despite its low surface brightness.
Why it matters for aurora viewing
Recognizing diffuse glow (stars shine through it; cameras show green) tells you the oval is overhead โ discrete displays may ignite from it.
See this in action on tonight's data.