Degree of ionization

This article deals with the degree of ionization in plasma physics. For the degree of dissociation , sometimes referred to as the same in chemistry , see there.

The degree of ionization (rarely also degree of ionization ) is a term from physics that is used specifically in plasma physics .

In plasma physics it is used to categorize plasmas and to describe different properties. It can assume values ​​between zero (completely neutral) and one (completely ionized, all electrons are free). However, the degree of ionization is not a simple quotient (e.g. in percent ) of two particle numbers or densities : Since atoms and molecules can be ionized several times and there are different ionization energies in gas mixtures , the individual parts of the gas contribute differently to the degree of ionization.

A frequently used mathematical formalism based on these considerations for determining the degree of ionization of a gas as a function of temperature , particle density and ionization energy is provided by the Saha equation .

Further information

• Ulrich Stroth: Plasma Physics . 1st edition. Vieweg + Teubner, Wiesbaden 2011, ISBN 978-3-8348-1615-3 .