Saha ionization equation

Saha equation ( Saha equation ionization ) describes the thermodynamic equilibrium depending on the degree of ionization of a gas by the temperature; reached the degree of ionization a significant magnitude, we no longer speak of a gas, but from a plasma. The equation was derived in 1920 by the then 27 -year-old Indian astrophysicist Meghnad Saha from the Boltzmann statistics and is important for the physics of stars.

You can read the Saha equation so that it is precisely those atoms are ionized, in which the thermal energy of the electrons is according to the Boltzmann distribution over the ionization energy.

Formulation

For pure gases is the Saha equation

With:

• The particle density of the ionized gas (where i is the number of missing electrons = ionization )
• The electron density
• The partition function of the atom / ion of the i-th stage
• The ionization energy that is required to another electron from an ion to remove ( i to i 1).
• The thermal wavelength ( an electron) with   the Planck constant
• The mass of an electron (constant)
• The thermal energy