STEVE

An acronym for Strong Thermal Emission Velocity Enhancement, which gives its name to an atmospheric optical phenomenon that occasionally occurs in the upper atmosphere and bears some resemblance to a polar aurora. It is an elongated, bright, purple luminous band, and there is still no fully satisfactory explanation for the phenomenon. From satellite data it has been possible to determine that STEVE is formed by a plasma at a temperature above 3000°C that flows at great speed, confined within that elongated structure some 25 km wide, formed at a little over 400 kilometers of altitude. Occasionally, STEVE appears alongside a green-colored aurora of the type that presents a structure known as a "picket fence," which allows one to deduce that both phenomena are interrelated.