gridfire::screening Namespace Reference

Classes
class	BareScreeningModel
	A screening model that applies no screening effect. More...
class	ScreeningModel
	An abstract base class for plasma screening models. More...
class	WeakScreeningModel
	Implements the weak screening model based on the Debye-Hückel approximation. More...

Typedefs
using	ADDouble = CppAD::AD<double>

Enumerations
enum class	ScreeningType { BARE , WEAK }
	Enumerates the available plasma screening models. More...

Functions
std::unique_ptr< ScreeningModel >	selectScreeningModel (ScreeningType type)
	A factory function to select and create a screening model.

Typedef Documentation

ADDouble

typedef CppAD::AD< double > gridfire::screening::ADDouble = CppAD::AD<double>

Enumeration Type Documentation

ScreeningType

enum class gridfire::screening::ScreeningType

strong

Enumerates the available plasma screening models.

This enum provides a set of identifiers for the different screening prescriptions that can be used in the reaction rate calculations.

Enumerator
BARE	No screening applied. The screening factor is always 1.0.
WEAK	Weak screening model (Salpeter, 1954). This model is suitable for non-degenerate, non-relativistic plasmas where the electrostatic potential energy between ions is small compared to their thermal kinetic energy. The screening enhancement factor is calculated as exp(H_12). Algorithm A composition-dependent term, ζ = ∑(Z_i^2 + Z_i) * Y_i, is calculated, where Z_i is the charge and Y_i is the molar abundance of each species. A prefactor is computed: prefactor = 0.188 * sqrt(ρ / T₇³) * sqrt(ζ), where ρ is the density and T₇ is the temperature in 10^7 K. For a reaction between two nuclei with charges Z₁ and Z₂, the enhancement term is H_12 = prefactor * Z₁ * Z₂. The final screening factor is exp(H_12). A special calculation is performed for the triple-alpha reaction.

Function Documentation

selectScreeningModel()

std::unique_ptr< ScreeningModel > gridfire::screening::selectScreeningModel

(

ScreeningType

type

)

A factory function to select and create a screening model.

This function returns a std::unique_ptr to a concrete implementation of the ScreeningModel abstract base class, based on the specified ScreeningType. This allows for easy switching between different screening prescriptions at runtime.

Parameters

type	The ScreeningType enum value specifying which model to create.

Returns

A std::unique_ptr<ScreeningModel> holding an instance of the requested screening model.

Algorithm The function uses a switch statement to determine which concrete model to instantiate. If the provided type does not match a known case, it defaults to creating a BareScreeningModel to ensure safe behavior.

Post-conditions

• A non-null std::unique_ptr<ScreeningModel> is always returned.

Usage

// Select the weak screening model
auto screening_model = gridfire::screening::selectScreeningModel(gridfire::screening::ScreeningType::WEAK);
 
// Use the model to calculate screening factors
// (assuming other parameters are initialized)
std::vector<double> factors = screening_model->calculateScreeningFactors(
    reactions, species, Y, T9, rho
);