piirkond Maa põhja- ja lõunapooluse läheduses, kus virmalised enamasti tekivad
the belt of maximum frequency of auroral visibility, approximately centered around the geomagnetic latitude of 67°, where the occurrence of auroras is most frequent
Piirkond, kus maakera magnetväli ohjab virmalisi ajendavaid magnetosfääri plasmakihi osakesi, moodustab kummagi magnetpooluse ümber ovaalse ala. Neid alasid kutsutakse virmaliste ovaalideks.
The auroral oval is the footprint in the atmosphere of the boundary between the highly stretched field lines of the polar cap and the more normal field lines at lower latitudes.
The southern counterpart, the aurora australis or the southern lights, has features almost identical to the aurora borealis and changes simultaneously with changes in the northern auroral zone.
