Emission coefficient

Emission coefficient

Emission coefficient is a coefficient in the power output per unit time of an electromagnetic source, a calculated value in physics. It is also used as a measure of environmental emissions (by mass) per MWh of electricity generated, see: Emission factor.

Scattering of light

In Thomson scattering a charged particle emits radiation under incident light. The particle may be an ordinary atomic electron, so emission coefficients have practical applications.

If "X" d"V" dΩ dλ is the energy scattered by a volume element d"V" into solid angle dΩ between wavelengths λ and λ+dλ per unit time then the Emission coefficient is "X".

The values of "X" in Thomson scattering can be predicted from incident flux, the density of the charged particles and their Thomson differential cross section (area/solid angle).

Spontaneous Emission

A warm body emitting photons has a monochromatic emission coefficient relating its temperature and total power radiation, this is sometimes called the second "Einstein coefficient", and can be deduced from quantum mechanical theory.

ee also

* The Diode equation includes the emission coefficient
* Plasma physics.
* An emission coefficient is also given for ballistic secondary electron emission.
* Luminous coefficient

External links

* [http://background.uchicago.edu/~whu/Courses/Ast305/ast305_01.pdf Astrophysics lecture slides on the emission coefficient] from University of Chicago.


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