thermodynamics

net.thermodynamics

The Thermodynamics object of a network: its equation of state and the heating rates and temperature rates derived from it. All attributes are built lazily on first access and cached.

from jaff import Network
from jaff.physics import EosProps

net = Network("COthin", eos_props=EosProps("ideal", gamma=5.0 / 3.0))
th = net.thermodynamics
th.eos.specific      # erg/g
th.dEdt_tot          # chemical + extra heating/cooling
th.dTdt_tot          # dT/dt including the composition term

Attribute	Type	Description
`eos`	`InternalEnergy`	Internal energy for the network's `eos_props` (ideal gas, \(\gamma = 1.6666666666667\), by default)
`dEdt_chemical`	`DEDt`	Chemical heating/cooling rate \(\sum_r dE_r F_r\) (erg cm⁻³ s⁻¹)
`dEdt_extra`	`DEDt`	Non-reactive rate from the `heatingcoolingrate` auxiliary function (else `0`)
`dEdt_tot`	`DEDt`	`dEdt_chemical + dEdt_extra`
`dTdt_chemical`	`sympy.Expr`	\((\dot{E}_\mathrm{chem} - \sum_i \partial E/\partial n_i\, \dot{n}_i) / (\partial E/\partial T)\) (K s⁻¹)
`dTdt_extra`	`sympy.Expr`	\(\dot{E}_\mathrm{extra} / (\partial E/\partial T)\) (K s⁻¹)
`dTdt_tot`	`sympy.Expr`	`dTdt_chemical + dTdt_extra`, built as one fraction

DEDt wraps a volumetric rate and offers the same normalised forms as InternalEnergy through normaliser(form); DEDt objects (and InternalEnergy objects) of the same class support + and -.

The code generator uses eos to form the temperature column of the Jacobian via the chain rule \(\partial \dot{x} / \partial e = (\partial \dot{x} / \partial T) / (\partial e / \partial T)\).

eos

net.thermodynamics.eos

Returns

InternalEnergy: Symbolic internal energy exposing the forms below (CGS units).

Property	Expression	Units
`volumetric`	\(E\)	erg cm⁻³
`specific`	\(E / \rho\)	erg g⁻¹
`per_particle`	\(E / n_\mathrm{tot}\)	erg
`molar`	\(N_A\, E / n_\mathrm{tot}\)	erg mol⁻¹

Each form is the volumetric energy divided by InternalEnergy.normaliser(form) (1, \(\rho\), \(n_\mathrm{tot}\) or \(n_\mathrm{tot}/N_A\)), which the code generator also uses to normalise dE/dt.

EosProps

EosProps(type, **kwargs)

Omitted parameters take the type's default (ideal: gamma = 1.6666666666667). Validated on construction: an unknown type, a missing or unexpected parameter, or an adiabatic index \(\le 1\) raises ValueError; a non-numeric index or a non-dict gamma_map raises TypeError.

`type`	Parameters	Volumetric energy
`ideal`	`gamma` (float > 1, default 1.6666666666667)	\(E = \dfrac{n_\mathrm{tot}\, k_B\, T_\mathrm{gas}}{\gamma - 1}\)
`multi_gamma`	`default_gamma` (float > 1), `gamma_map` (dict[str, float > 1])	per-species sum; `gamma_map` keyed by species name, falling back to `default_gamma`
`fermi_degenerate`	—	not implemented
`relativistic_fermi_degenerate`	—	not implemented