A simple parameterisation of N-Pole outer yoke magnetic field. More...

#include <BDSFieldMagMultipoleOuter.hh>

Inheritance diagram for BDSFieldMagMultipoleOuter:

Collaboration diagram for BDSFieldMagMultipoleOuter:

Public Member Functions
	BDSFieldMagMultipoleOuter (G4int orderIn, G4double poleTipRadius, const BDSFieldMag *innerFieldIn, G4bool kPositive, G4double bRho, G4double arbitraryScaling=1.0)

virtual G4ThreeVector	GetField (const G4ThreeVector &position, const double t=0) const
	Access the field value.

Public Member Functions inherited from BDSFieldMag
	BDSFieldMag ()

	BDSFieldMag (G4Transform3D transformIn)

virtual G4ThreeVector	GetField (const G4ThreeVector &position, const G4double t=0) const =0

virtual G4bool	TimeVarying () const

virtual void	GetFieldValue (const G4double point[4], G4double *field) const

virtual G4ThreeVector	GetFieldTransformed (const G4ThreeVector &position, const G4double t) const
	Get the field value after applying transform for local offset.

virtual void	SetTransform (const G4Transform3D &transformIn)

void	SetModulator (BDSModulator *modulatorIn)
	Set the optional modulator.

G4bool	FiniteStrength () const
	Accessor.

Private Attributes
const G4int	order
	N-poles / 2.

G4double	phiOffset
	Tilt in XY calculated from B vector of inner field. if B0=(0,1,0), phiOffset=0.

G4double	spatialLimit
	Radius from any current source within which the field is artificially saturated.

G4double	normalisation
	Storage of the overall normalisation factor.

G4bool	positiveField
	Sign of magnetic field.

G4int	poleNOffset
	Offset for pole to start at - in effect this flips the sign of the field.

G4double	poleTipRadius
	Radius of transition between inner and outer fields.

std::vector< G4TwoVector >	currents
	Locations of infinite wire current sources.

G4double	maxField
	Any field beyond this will curtailed to this value.

G4bool	initialisationPhase
	Need a way to control cludge normalisation behaviour during initial normalisation calculation.

Additional Inherited Members
Protected Attributes inherited from BDSFieldMag
G4bool	finiteStrength
	Flag to cache whether finite nor not.

G4Transform3D	transform
	Transform to apply for the field relative to the local coordinates of the geometry.

G4bool	transformIsNotIdentity
	Cache of whether to use transform at all.

BDSModulator *	modulator
	Optional modulator;.

Detailed Description

A simple parameterisation of N-Pole outer yoke magnetic field.

Field that roughly approximates the field in a yoke of an n-pole magnet. The field is generated by the linear sum of infinitely long wire current sources along +-z (local) placed at a radius of poleTipRadius according to the order of the magnet. Note, these current sources are placed exactly in between the pole will be for each type of magnet. The field is normalised to the field at the pole tip radius given innerFieldIn.

If a point close (< 6mm) to a pole is queried, the field is capped at the normalised value at the pole tip - assumed to be the highest value.

This field of course does not accurately represent the field in the yoke of a magnet as it neglects the permeability and the geometry, however, it is a 1st order approximation.

Does not own or delete the BDSFieldMag* innerFieldIn argument.

Author: Laurie Nevay

Definition at line 55 of file BDSFieldMagMultipoleOuter.hh.

Constructor & Destructor Documentation

◆ BDSFieldMagMultipoleOuter()

BDSFieldMagMultipoleOuter::BDSFieldMagMultipoleOuter	(	G4int	orderIn,
		G4double	poleTipRadius,
		const BDSFieldMag *	innerFieldIn,
		G4bool	kPositive,
		G4double	bRho,
		G4double	arbitraryScaling = `1.0`
	)