Struct RhoECoupling

pub struct RhoECoupling {
    pub rho_e_old: f64,
    pub r_compton: f64,
    pub rho_source: f64,
    pub lambda_exp: f64,
    pub dh_drho: f64,
    pub h_norm: f64,
}

Parameters for coupling ρ_e into the bordered Newton system.

When passed to kompaneets_step_coupled_inplace, ρ_e becomes the (N+1)-th unknown solved simultaneously with Δn. The system becomes bordered tridiagonal, solved in O(N) via two Thomas solves.

Fields

rho_e_old: f64

ρ_e at the start of this timestep (before update_temperatures).

r_compton: f64

Compton coupling coefficient R = (8/3)(ρ̃_γ/α_h). This is the rate at which Compton scattering drives ρ_e → ρ_eq, per unit Thomson optical depth.

rho_source: f64

Source term in the ρ_e ODE: R·ρ_eq + δρ_inj.

lambda_exp: f64

Adiabatic cooling rate: H·t_C.

dh_drho: f64

dH_dcbr/dρ_e (finite-difference derivative from update_temperatures).

h_norm: f64

Normalization for H_dcbr integral: 1/(4·G₃·θ_z).