Townsend coefficients

The three Townsend coefficients ( first Townsend coefficient , etc.), named after John Sealy Townsend , describe the properties of gas discharges under the influence of an external electric field in the physics of plasmas : ${\displaystyle \alpha }$

• ${\displaystyle \alpha }$- probability per path length , with the new free electrons through impact with other charge carriers are generated
• ${\displaystyle \beta }$- Probability per path length with which new free electrons are generated by collision with neutral particles; is often neglected because it is very small compared to ${\displaystyle \alpha }$
• ${\displaystyle \gamma }$- a material constant that indicates how many electrons are released per ion .

You can find e.g. B. in Paschen's law application.

Further information

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