PlasmaMLPALLASMagneticField Class Reference

Defines the magnetic field model for the PALLAS simulation. More...

#include <PlasmaMLPALLASMagneticField.hh>

Inheritance diagram for PlasmaMLPALLASMagneticField:

Collaboration diagram for PlasmaMLPALLASMagneticField:

Public Member Functions
	PlasmaMLPALLASMagneticField ()
	Constructor.
	~PlasmaMLPALLASMagneticField () override
	Destructor.
void	GetFieldValue (const G4double point[4], double *bField) const override
	Compute the magnetic field at a given location.
void	SetDipoleField (G4double val)
	Set the constant dipole magnetic field value.
void	SetGradient (size_t index, G4double gradient)
	Set the gradient of a quadrupole.
G4double	GetGradient (size_t index) const
	Get the gradient of a quadrupole.
void	SetQLength (size_t index, G4double length)
	Set the length of a quadrupole.
G4double	GetQLength (size_t index) const
	Get the length of a quadrupole.
void	SetQDrift (size_t index, G4double drift)
	Set the drift distance before a quadrupole.
G4double	GetQDrift (size_t index) const
	Get the drift distance before a quadrupole.
void	SetMapBFieldStatus (G4bool val)
	Enable or disable mapped magnetic field usage.

Detailed Description

Defines the magnetic field model for the PALLAS simulation.

Implements the PALLAS magnetic field configuration for dipole and quadrupole elements.

Author

Arnaud HUBER huber.nosp@m.@lp2.nosp@m.ib.in.nosp@m.2p3..nosp@m.fr - Alexei SYTOV sytov.nosp@m.@inf.nosp@m.n.it

Date

2025

Copyright

PALLAS Project - GEANT4 Collaboration

This header declares the PlasmaMLPALLASMagneticField class, which extends Geant4's G4MagneticField to provide a configurable representation of the magnetic fields in the beamline, including dipole and quadrupole elements.

Responsibilities:

• Store and provide access to magnetic field parameters (dipole strength, quadrupole gradients, lengths, drifts)
• Compute the field value at any given point for use in particle tracking
• Allow toggling between constant-field mode and mapped-field mode
• Provide fitting functions for magnetic field profile parameterization

Key features:

• Configurable for up to four quadrupoles (NumQuadrupoles)
• Units consistent with CLHEP system (tesla, mm, etc.)
• Command interface for runtime parameter changes

Note

This class is typically used by the geometry and tracking systems in conjunction with Geant4's field propagation.

This class allows setting and retrieving the parameters of dipole and quadrupole fields and calculates the magnetic field vector at any requested point.

Constructor & Destructor Documentation

PlasmaMLPALLASMagneticField()

PlasmaMLPALLASMagneticField::PlasmaMLPALLASMagneticField

(

)

Constructor.

Default constructor.

~PlasmaMLPALLASMagneticField()

PlasmaMLPALLASMagneticField::~PlasmaMLPALLASMagneticField ( )

override

Destructor.

Member Function Documentation

GetFieldValue()

void PlasmaMLPALLASMagneticField::GetFieldValue ( const G4double  point[4], double *  bField  ) const

override

Compute the magnetic field at a given location.

Compute the magnetic field at a given point.

Parameters

point	Position (and time) array [x, y, z, t] in global coordinates
bField	Output array [Bx, By, Bz] to store field components in tesla

Computes dipole and quadrupole contributions based on current configuration.

Parameters

point	Array [x,y,z,t] with position and time
bField	Output array [Bx,By,Bz]

GetGradient()

G4double PlasmaMLPALLASMagneticField::GetGradient

(

size_t

index

)

const

Get the gradient of a quadrupole.

Get gradient of a quadrupole.

Parameters

index

Quadrupole index (0-based, < NumQuadrupoles)

Returns

Gradient value in tesla/meter

Parameters

index

Quadrupole index (0-based)

Returns

Gradient in tesla/m

GetQDrift()

G4double PlasmaMLPALLASMagneticField::GetQDrift

(

size_t

index

)

const

Get the drift distance before a quadrupole.

Get drift distance before a quadrupole.

Parameters

index

Quadrupole index (0-based, < NumQuadrupoles)

Returns

Drift distance in mm

Parameters

index

Quadrupole index (0-based)

Returns

Drift distance in meters

GetQLength()

G4double PlasmaMLPALLASMagneticField::GetQLength

(

size_t

index

)

const

Get the length of a quadrupole.

Parameters

index

Quadrupole index (0-based, < NumQuadrupoles)

Returns

Length in mm

Parameters

index

Quadrupole index (0-based)

Returns

Length in meters

SetDipoleField()

void PlasmaMLPALLASMagneticField::SetDipoleField

(

G4double

fieldValue

)

Set the constant dipole magnetic field value.

Set the constant dipole field.

Parameters

val	Field strength in tesla
fieldValue	Dipole field in tesla

SetGradient()

void PlasmaMLPALLASMagneticField::SetGradient	(	size_t	index,
		G4double	gradient
	)

Set the gradient of a quadrupole.

Set gradient of a quadrupole.

Parameters

index	Quadrupole index (0-based, < NumQuadrupoles)
gradient	Gradient value in tesla/meter
index	Quadrupole index (0-based)
gradient	Gradient in tesla/m

SetMapBFieldStatus()

void PlasmaMLPALLASMagneticField::SetMapBFieldStatus

(

G4bool

status

)

Enable or disable mapped magnetic field usage.

Enable or disable mapped-field mode.

Parameters

val	True to use a field map, false for constant/parameterized fields
status	True for mapped-field, false for constant/parameterized

SetQDrift()

void PlasmaMLPALLASMagneticField::SetQDrift	(	size_t	index,
		G4double	drift
	)

Set the drift distance before a quadrupole.

Set drift distance before a quadrupole.

Parameters

index	Quadrupole index (0-based, < NumQuadrupoles)
drift	Distance in mm
index	Quadrupole index (0-based)
drift	Drift distance in meters

SetQLength()

void PlasmaMLPALLASMagneticField::SetQLength	(	size_t	index,
		G4double	length
	)

Set the length of a quadrupole.

Parameters

index	Quadrupole index (0-based, < NumQuadrupoles)
length	Length in mm
index	Quadrupole index (0-based)
length	Length in meters

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

• include/PlasmaMLPALLASMagneticField.hh
• src/PlasmaMLPALLASMagneticField.cc