local thermodynamic equilibrium (LTE)
tarâzmandi-ye garmâtavânik-e mahali
Fr.: équilibre thermodynamique local
The assumption that all distribution functions characterizing the material and its interaction with the radiation field at a point in the star are given by → thermodynamic equilibrium relations at local values of the temperature and density.
non-local thermodynamic equilibrium (NLTE)
tarâzmandi-ye garmâtavânik-e nâmahali
Fr.: hors équilibre thermodynamique local
A physical condition in which the assumption of the → local thermodynamic equilibrium does not hold.
Fr.: équilibre thermodynamique
The condition of a → thermodynamic system in which the available → energy is distributed uniformly among all the possible forms of energy. Furthermore, all → thermodynamic process es must be exactly balanced by their reverse processes. For example, inside a star there will be as many → ionizations of helium per second as there are → recombinations of free electrons and helium ions. Se also → local thermodynamic equilibrium (LTE).