Corona discharge Corona discharge A corona discharge is an electrical discharge brought on by the ionization of a fluid such as air surrounding a conductor that is electrically charged. Spontaneous corona discharges occur naturally in high-voltage systems unless care is taken to limit the electric field strength. A corona will occur when the strength of the electric field (potential gradient) around a conductor is high enough to form a conductive region, but not high enough to cause electrical breakdown or arcing to nearby objects. It is often seen as a bluish (or other color) glow in the air adjacent to pointed metal
Collis (planetary nomenclature) Venus and 5 on Titan. On different celestial bodies they are named differently: Collis (planetary nomenclature) Collis (plural: colles, from the Latin word for "hill") is a small hill or knob on a celestial body. The term is used in planetary nomenclature: it is a part of international proper names of such features. Like other generic terms, it is capitalized and stands after the proper name (for example, "Bilbo Colles"; the only exception is "Colles Nili" on Mars). As of 2015, only groups of the hills have names, and the term is used only in plural. Like the other terms