We don't have synonyms for red sprite yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are red sprites, red spruce and red stripe.
(n) :
(astronomy, meteorology) An upper atmospheric optical phenomena associated with thunderstorms, a large but weak luminous flash that appears directly above an active thunderstorm system and is coincident with a powerful positive cloud-to-ground lightning strike.
(n) :
(astronomy, meteorology) An upper atmospheric optical phenomena associated with thunderstorms, a large but weak luminous flash that appears directly above an active thunderstorm system and is coincident with a powerful positive cloud-to-ground lightning strike.