Neutrino Losses

We model thermal neutrino losses (plasma, photo-, pair-, recombination, and Bremsstrahlung) using the method described in [31]. This neutrino loss term is included in all of the reaction networks by default, and modifies the energy equation to have the form (for Strang splitting):

$$\frac{de}{dt}=ϵ-{ϵ}_{\nu }$$

where ${ϵ}_{\nu }$ are the thermal neutrino losses.

Note

Thermal neutrino losses can be disabled at compile time by setting the make variable USE_NEUTRINOS = FALSE.

The interface for the neutrino loss function is:

template <int do_derivatives>
AMREX_GPU_HOST_DEVICE AMREX_INLINE
void sneut5(const amrex::Real temp, const amrex::Real den,
            const amrex::Real abar, const amrex::Real zbar,
            amrex::Real& snu, amrex::Real& dsnudt, amrex::Real& dsnudd,
            amrex::Real& dsnuda, amrex::Real& dsnudz)

Here, the template parameter, do_derivatives, can be used to disable the code the computes the derivatives of the neutrino loss, for example, if a numerical Jacobian is used. The output is

• snu : ${ϵ}_{\nu }$, the neutrino loss in erg/g/s

• dsnudt : $d{ϵ}_{\nu }/dT$

• dsnudd : $d{ϵ}_{\nu }/d\rho$

• dsnuda : $d{ϵ}_{\nu }/d\overline{A}$

• dsnudz : $d{ϵ}_{\nu }/d\overline{Z}$