Plasma recombination

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Plasma recombination is a process by which ions of a plasma capture the free energetic electrons to form new neutral atoms.

Recombination usually take place in the whole volume of a plasma (volume recombination), although in some cases it is confined to some special region of it. Each kind of reaction is called a recombining mode and their individual rates are strongly affected by the properties of the plasma such as its energy (Thermal energy), density of each species, pressure and temperature of the surrounding environment. Especially volume recombination is a very unlikely process at pressures below 1×10⁴ Pa because of the conservation of energy and momentum. A third body is needed to satisfy the conservation laws. If the volume of the plasma is confined by a body the walls play the role of the third body. So recombination mostly occurs at the walls.

Hydrogen recombination modes are of vital importance in the development of divertor regions for tokamak reactors. In fact they will provide a good way for extracting the energy produced in the core of the plasma. At the present time, it is believed that the most likely plasma losses observed in the recombining region are due to two different modes: electron ion recombination (EIR) and molecular activated recombination (MAR).