GrainComposition Class Reference

#include <GrainComposition.hpp>

Inheritance diagram for GrainComposition:

Public Member Functions
virtual double	bulkDensity () const =0
virtual string	name () const =0
virtual string	resourceNameForEnthalpies () const =0
virtual string	resourceNameForMuellerMatrix () const
virtual string	resourceNameForOpticalProps () const =0
virtual bool	resourcesForSpheroidalEmission (bool &resource, double &interpol, string &tableName1, string &tableName2) const
Public Member Functions inherited from SimulationItem
template<class T >
T *	find (bool setup=true) const
template<class T >
T *	interface (int levels=-999999, bool setup=true) const
virtual string	itemName () const
void	setup ()
string	typeAndName () const
Public Member Functions inherited from Item
	Item (const Item &)=delete
virtual	~Item ()
void	addChild (Item *child)
const vector< Item * > &	children () const
virtual void	clearItemListProperty (const PropertyDef *property)
void	destroyChild (Item *child)
virtual bool	getBoolProperty (const PropertyDef *property) const
virtual vector< double >	getDoubleListProperty (const PropertyDef *property) const
virtual double	getDoubleProperty (const PropertyDef *property) const
virtual string	getEnumProperty (const PropertyDef *property) const
virtual int	getIntProperty (const PropertyDef *property) const
virtual vector< Item * >	getItemListProperty (const PropertyDef *property) const
virtual Item *	getItemProperty (const PropertyDef *property) const
virtual string	getStringProperty (const PropertyDef *property) const
int	getUtilityProperty (string name) const
virtual void	insertIntoItemListProperty (const PropertyDef *property, int index, Item *item)
Item &	operator= (const Item &)=delete
Item *	parent () const
virtual void	removeFromItemListProperty (const PropertyDef *property, int index)
virtual void	setBoolProperty (const PropertyDef *property, bool value)
virtual void	setDoubleListProperty (const PropertyDef *property, vector< double > value)
virtual void	setDoubleProperty (const PropertyDef *property, double value)
virtual void	setEnumProperty (const PropertyDef *property, string value)
virtual void	setIntProperty (const PropertyDef *property, int value)
virtual void	setItemProperty (const PropertyDef *property, Item *item)
virtual void	setStringProperty (const PropertyDef *property, string value)
void	setUtilityProperty (string name, int value)
virtual string	type () const

Protected Member Functions
	GrainComposition ()
Protected Member Functions inherited from SimulationItem
	SimulationItem ()
virtual bool	offersInterface (const std::type_info &interfaceTypeInfo) const
virtual void	setupSelfAfter ()
virtual void	setupSelfBefore ()
Protected Member Functions inherited from Item
	Item ()

Private Types
using	BaseType = SimulationItem
using	ItemType = GrainComposition

Friends
class	ItemRegistry

Detailed Description

GrainComposition is an abstract class that represents the optical and calorimetric properties of a population of dust grains with a given material composition.

The basic optical properties are provided for arbitrary grain sizes and at arbitrary wavelengths; in practice, they are defined on a two-dimensional grid of wavelengths \(\lambda_k\) and grain sizes \(a_i\). The basic optical properties include the absorption and scattering efficiencies \(Q_{k,i}^{\text{abs}}\) and \(Q_{k,i}^{\text{sca}}\) and the scattering phase function asymmetry parameter \(g_{k,i}\). All of these quantities are dimensionless.

Optionally, a grain composition may provide the four coefficients \(S_{xx}\) of the Mueller matrix for spherical grains, as a function of wavelength, grain size, and scattering angle. A dust mix containing grain compositions that provide the Mueller matrix coefficients can support the MaterialPhaseFunction and SphericalPolarization scattering modes, in addition to the HenyeyGreenstein scattering mode (see the MaterialMix class for more information on scattering modes).

Furthermore, a grain composition may optionally provide additional properties relevant for calculating the polarization effects of scattering, absorption and emission by spheroidal grains. The current implementation supports only the properties relevant for polarized emission, i.e the absorption efficiencies \(Q^\mathrm{abs}(a,\lambda,\theta)\) and the corresponding linear polarization efficiencies \(Q^\mathrm{abspol}(a,\lambda,\theta)\) as a function of grain size \(a\), wavelength \(\lambda\) and emission angle \(\theta\). For consistency, the \(Q^\mathrm{abs}\) values given here, when averaged over the emission angle, should match the basic \(Q^\mathrm{abs}\) mentioned above.

The calorimetric properties consist of the specific enthalpy (internal energy) per unit volume, given in J/m3, at arbitrary temperature. The specific enthalpy is obtained by integrating the specific heat capacity of the material over the temperature range, using an arbitrary zero point. In practice, the specific enthalpy is defined on a grid of temperatures \(T_t\) resulting in a set of values \(h_t\).

A final, key property is the bulk mass density \(\rho_\text{bulk}\) of the grain material, a single value given in kg/m3. To obtain the specific enthalpy per unit of mass (J/kg) from the provided specific enthalpy per unit volume (J/m3), one needs to divide the provided values by the bulk mass density (in kg/m3). Also, the same bulk mass density value must be used for calculating the dust mass from the size distribution to obtain consistent results.

The GrainComposition class provides a public interface for retrieving the resource names for the various tables mentioned above, and for retrieving the value of the bulk mass density. Subclasses are required to implement these functions appropriately.

Constructor & Destructor Documentation

GrainComposition()

GrainComposition::GrainComposition ( )

inlineprotected

Default constructor for abstract Item subclass GrainComposition : "a dust grain composition" .

Member Function Documentation

bulkDensity()

virtual double GrainComposition::bulkDensity ( ) const

pure virtual

This function returns the bulk mass density \(\rho_\text{bulk}\) of the grain material.

Implemented in BegemannPorousAluminaGrainComposition, CrystalEnstatiteGrainComposition, CrystalForsteriteGrainComposition, DorschnerOlivineGrainComposition, DraineGraphiteGrainComposition, DraineIonizedPAHGrainComposition, DraineNeutralPAHGrainComposition, DraineSilicateGrainComposition, DustEmGrainComposition, HofmeisterPericlaseGrainComposition, MieSilicateGrainComposition, MinSilicateGrainComposition, PolarizedGraphiteGrainComposition, PolarizedSilicateGrainComposition, TrustGraphiteGrainComposition, TrustNeutralPAHGrainComposition, and TrustSilicateGrainComposition.

name()

virtual string GrainComposition::name ( ) const

pure virtual

This function returns a brief human-readable identifier for the type of grain composition represented by the instance. The identifier is not allowed to contain white space.

Implemented in BegemannPorousAluminaGrainComposition, CrystalEnstatiteGrainComposition, CrystalForsteriteGrainComposition, DorschnerOlivineGrainComposition, DraineGraphiteGrainComposition, DraineIonizedPAHGrainComposition, DraineNeutralPAHGrainComposition, DraineSilicateGrainComposition, DustEmGrainComposition, HofmeisterPericlaseGrainComposition, MieSilicateGrainComposition, MinSilicateGrainComposition, PolarizedGraphiteGrainComposition, PolarizedSilicateGrainComposition, SpheroidalGraphiteGrainComposition, SpheroidalSilicateGrainComposition, TrustGraphiteGrainComposition, TrustNeutralPAHGrainComposition, and TrustSilicateGrainComposition.

resourceNameForEnthalpies()

virtual string GrainComposition::resourceNameForEnthalpies ( ) const

pure virtual

This function returns the name of the stored table resource tabulating the specific enthalpies per unit volume as a function of temperature.

Implemented in BegemannPorousAluminaGrainComposition, CrystalEnstatiteGrainComposition, CrystalForsteriteGrainComposition, DorschnerOlivineGrainComposition, DraineGraphiteGrainComposition, DraineIonizedPAHGrainComposition, DraineNeutralPAHGrainComposition, DraineSilicateGrainComposition, DustEmGrainComposition, HofmeisterPericlaseGrainComposition, MieSilicateGrainComposition, MinSilicateGrainComposition, PolarizedGraphiteGrainComposition, PolarizedSilicateGrainComposition, TrustGraphiteGrainComposition, TrustNeutralPAHGrainComposition, and TrustSilicateGrainComposition.

resourceNameForMuellerMatrix()

virtual string GrainComposition::resourceNameForMuellerMatrix ( ) const

virtual

This function returns the name of the stored table resource tabulating the coefficients of the Mueller matrix as a function of wavelength, grain size, and scattering angle. This function is invoked for the MaterialPhaseFunction scattering mode (to obtain \(S_{11}\) ) and for the SphericalPolarization scattering mode (to obtain all four \(S_{xx}\) coefficients). The default implementation in this base class returns the empty string, indicating that only the HenyeyGreenstein scattering mode can be used.

Reimplemented in PolarizedGraphiteGrainComposition, and PolarizedSilicateGrainComposition.

resourceNameForOpticalProps()

virtual string GrainComposition::resourceNameForOpticalProps ( ) const

pure virtual

This function returns the name of the stored table resource tabulating the basic optical properties (absorption and scattering efficiencies and asymmetry parameter) as a function of wavelength and grain size. The asymmetry parameter values are used only with the HenyeyGreenstein scattering mode.

Implemented in BegemannPorousAluminaGrainComposition, CrystalEnstatiteGrainComposition, CrystalForsteriteGrainComposition, DorschnerOlivineGrainComposition, DraineGraphiteGrainComposition, DraineIonizedPAHGrainComposition, DraineNeutralPAHGrainComposition, DraineSilicateGrainComposition, DustEmGrainComposition, HofmeisterPericlaseGrainComposition, MieSilicateGrainComposition, MinSilicateGrainComposition, PolarizedGraphiteGrainComposition, PolarizedSilicateGrainComposition, TrustGraphiteGrainComposition, TrustNeutralPAHGrainComposition, and TrustSilicateGrainComposition.

resourcesForSpheroidalEmission()

virtual bool GrainComposition::resourcesForSpheroidalEmission ( bool &  resource, double &  interpol, string &  tableName1, string &  tableName2  ) const

virtual

This function returns information on the resources required for implementing thermal emission from aligned spheriodal grains. It is invoked for the SpheroidalPolarization scattering mode. If the grain composition does not support this mode, the function returns false and the output arguments remain unchanghed. If the grain composition does support this mode, the function returns true and the output arguments are updated as follows:

• resource: true if the specified tables are built-in resources or false if they are provided as user input files.
• interpol: the interpolation fraction between the two tables in range [0,1]; the value is used to linearly interpolate between the two tables. A value of 0 means that the second table is ignored, a value of 1 means that the first table is ignored. A value in between is used to linearly interpolate between the two tables.
• tableName1: the name of the first stored table (resource or user input file); this name must always be provided (i.e. non-empty and valid) even if interpol is equal to 1.
• tableName2: the name of the second stored table (resource or user input file); this name may be missing (i.e. the empty string) if interpol is equal to 0.

Each of the stored tables tabulates the absorption efficiencies \(Q^\mathrm{abs}(a,\lambda,\theta)\) and the corresponding linear polarization efficiencies \(Q^\mathrm{abspol}(a,\lambda,\theta)\) as a function of grain size \(a\), wavelength \(\lambda\) and emission angle \(\theta\).

The default implementation in this base class returns false and does not change the output arguments, indicating that there is no support for spheroidal grains.

Reimplemented in SpheroidalGraphiteGrainComposition, and SpheroidalSilicateGrainComposition.

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The documentation for this class was generated from the following file:

• GrainComposition.hpp