An electron avalanche is a process in which a number of free electrons in a medium (usually a gas) are subjected to a strong electric field accelerate, ionizing the mediums' atoms by collision (creating positive ions), forming "new" electrons to undergo the same process in successive cycles. This ionization , and a free electron. Streamers in lightning discharges propagate by formation of electron avalanches. The streamers' high electric field strength moves ahead of the advancing tips. Avalanche processes are intensified in value or beauty and quality by formation of photoelectrons as a result of ultraviolet radiation emitted by the excited medium's atoms in the aft-tip region In physics, the free electron model is a possible model for the behaviour of electrons in a crystal structure. ... The word medium has a number of uses: Medium is an average or mean in a range of sizes or conditions. ... A gas is one of the phases of matter. ... In physics, an electric field or E-field is an effect produced by an electric charge that exerts a force on charged objects in its vicinity. ... An ion is an atom or group of atoms with a net electric charge. ... Lightning over Pentagon City in Arlington County, Virginia Cloud to cloud lightning Lightning is a powerful natural electrostatic discharge produced during a thunderstorm. ...

These high-energy electrons, accelerated by the field, (whichever their direction of travel) often collide with neutral atoms inelastically, potentially ionizing those atoms. In a chain-reaction - or 'electron avalanche' - those additional electrons are also separated from their positive ions by the strong potential gradient, causing a large cloud of electrons and positive ions to be momentarily generated by just a single initial event. Several things have been named Chain Reaction, after the chain reaction process best known in connection with nuclear fission: Chain Reaction, a film Chain Reaction, a 1990s record label Chain Reaction, a 1980s game show Chain Reaction, a 1970s band A Square Dance Call on the A1 List A Series...

Avalanche sustenance requires a reservoir of charge. A number of mechanisms can sustain this process, creating avalanche after avalanche, to create a constant corona current. A secondary source of plasma electrons is required as the electrons are always accelerated by the field in one direction, meaning that avalanches always proceed linearly toward or away from an electrode. The dominant mechanism for the creation of secondary electrons depends on the polarity of a plasma. In each case, the energy emitted as photons by the initial avalanche is used to ionise a molecule creating another accelerable electron. What differs is the source of this electron.

A plasma begins with a rare natural 'background' ionization event of a neutral air molecule, perhaps as the result of photo-excitation or background radiation. If this event occurs in an area with a high potential gradient, the positive ion will be strongly attracted toward, or repelled away from, the curved electrode (depending on the polarity of the corona), whereas the electron will be attracted in the opposite direction. This will, occasionally, prevent the recombination of electron and positive ion. Background radiation is the ionizing radiation from several natural radiation sources: sources in the Earth and from those sources that are incorporated in our food and water, which are incorporated in our body, and in building materials and other products that incorporate those radioactive sources; radiation sources from space (in...