Radiative Equilibrium

The radiative energy is related to the radiative temperature by (is this always the case?):

E_{rad}=a T_{rad} ^4

(where the radiative energy is the total radiative energy, i.e. the sum of any blackbody radiation, as well as any sources — what else is a source of radiation in the code?)

In radiative equlibrium, the radiative temperature equals the gas temperature,

T_{rad}=T_{gas}

That is to say,

E_{rad}=a T_{gas}^4

However, in general the energies of the gas and the radiation will not be equal. In radiative equilibrium, the gas energy,

E_{gas}=n K_B T_{gas}

will equal the radiative energy,

E_{rad}=a T_{gas}^4

when

n K_B=a T_{gas}^3

Depending on the ratio of Erad/Egas, will get different rates at which the temperature will rise (right?). This is in addition to the coupling.