Saint Elmo's fire


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Saint Elmo's fire,

luminous discharge of electricity extending into the atmosphere from some projecting or elevated object. It is usually observed (often during a snowstorm or a dust storm) as brushlike fiery jets extending from the tips of a ship's mast or spar, a wing, propeller, or other part of an aircraft, a steeple, a mountain top, or even from blades of grass or horns of cattle. Sometimes it plays about the head of a person, causing a tingling sensation. The phenomenon occurs when the atmosphere becomes charged and an electrical potential strong enough to cause a discharge is created between an object and the air around it. The amount of electricity involved is not great enough to be dangerous. The appearance of St. Elmo's fire is regarded as a portent of bad weather. The phenomenon, also known as corposant, was long regarded with superstitious awe.

Saint Elmo’s Fire

 

electrical discharges in the atmosphere in the form of flashing brushes occasionally observed on high pointed objects, such as towers, masts, lone trees, and mountain tops. The phenomenon was named in the Middle Ages after Saint Elmo’s Church, on the towers of which it was frequently observed.

Saint Elmo’s fire arises when the electrostatic intensity in the atmosphere at a point reaches a magnitude of the order of 500 volts per meter or higher, which occurs most often during thunderstorms or upon the approach of such storms; in the winter, it occurs during blizzards. Physically, Saint Elmo’s fire is a special type of corona discharge (seeCORONA DISCHARGE).

Saint Elmo's fire

[′sānt ′el·mōz ′fīr]
(electricity)
A visible electric discharge, sometimes seen on the mast of a ship, on metal towers, and on projecting parts of aircraft, due to concentration of the atmospheric electric field at such projecting parts.