Solar plage

[1] The term plage is often believed to be poetically taken from the French word for "beach"; however, this is likely a misunderstanding of an 1893 article by Henri-Alexandre Deslandres where the name facular flames was suggested.

In the article, Deslandres also refers to them as plages brillantes, meaning bright regions, which became the more commonly used term.

[2] Classically, plage have been defined as regions that are bright in Hα and other chromospheric emission lines.

With modern imaging, most researchers now identify plage based on the photospheric magnetic field concentration of the faculae below.

[3][4] It is believed that plage is formed from decaying emerging flux regions, and often acts as a footprint for coronal loops and fibrils, which makes them an important interface for coronal heating.