A self-sustained low energy electrical discharge with non-thermal ionization that takes place in the vicinity of an electrode of sufficiently low radius of curvature, in a medium whose presence is typ [..]

 - An electrical discharge at the surface of a conductor accompanied by the ionization of the surrounding atmosphere. It can be accompanied by light and audible noise.

a luminous discharge which occurs when the applied voltage is high enough (5000 volts or more) to cause partial ionization of the surrounding gas

Strong local electric fields cause ionization in the vicinity of an electrode. Within this area a plasma is formed from this gas. The electric field between this electrode and a second electrode is not strong enough to cause an electric breakdown, but within the Corona objects can be corona treated, especially activated.        

A type of air purifier that uses ozone to clean the air. The air inside a coronal discharge device is charged with between 5,000 and 10,000 volts of electricity. The shock causes unstable bonds to for [..]

See CORONA DISCHARGE, ST. ELMO’S FIRE.

A localized cold discharge in air which forms around grounded objects producing an enhancement in electric field strength to allow ionization growth. Called St. Elmos's Fire by ancient mariners. [..]

Bluish white luminous discharge which appears surrounding a conductor surface at a field exceeding corona inception, but not being sufficient to cause sparking or flash over.

(electricity) The ionization of air (or any other fluid) surrounding an electrically energized conductor, as a result of a strong electric field.