### Boltzmann Transport Equation

**(BTE, Boltzmann_equation)**
(equation for evolving distribution of gas particles)

The **Boltzmann Transport Equation** (**BTE**, also called the
**Boltzmann Equation**)
is an equation describing the distribution of the velocity
of particles in a gas, but is more general than the
Maxwell-Boltzmann distribution because it does not presume
equilibrium. It describes the distribution over time and converges
with the Maxwell Boltzmann distribution if equilibrium is reached,
i.e., the distribution is in a state where it tends to remain the
same. The equation has clear uses in astrophysics when an object
such as a cloud or star lacks or loses its equilibrium, but has also
been borrowed for use in stellar dynamics in galaxies and
stellar clusters, taking stars as the particles.

Note that another use of the term **Boltzmann equation** is
for an equation modeling the distribution of atomic excitation
levels in a gas.

(*physics,mathematics*)
**Further reading:**

http://en.wikipedia.org/wiki/Boltzmann_equation

**Referenced by pages:**

Boltzmann equation

CMBFAST

Vlasov-Poisson equation

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