Geant4-11
Public Member Functions | Private Attributes
G4EqEMFieldWithSpin Class Referenceabstract

#include <G4EqEMFieldWithSpin.hh>

Inheritance diagram for G4EqEMFieldWithSpin:
G4EquationOfMotion

Public Member Functions

virtual void EvaluateRhsGivenB (const G4double y[], const G4double B[3], G4double dydx[]) const =0
 
void EvaluateRhsGivenB (const G4double y[], const G4double Field[], G4double dydx[]) const
 
void EvaluateRhsReturnB (const G4double y[], G4double dydx[], G4double Field[]) const
 
 G4EqEMFieldWithSpin (G4ElectroMagneticField *emField)
 
G4double GetAnomaly () const
 
G4Field * GetFieldObj ()
 
const G4Field * GetFieldObj () const
 
void GetFieldValue (const G4double Point[4], G4double Field[]) const
 
void RightHandSide (const G4double y[], G4double dydx[]) const
 
void SetAnomaly (G4double a)
 
void SetChargeMomentumMass (G4ChargeState particleCharge, G4double MomentumXc, G4double mass)
 
void SetFieldObj (G4Field *pField)
 
 ~G4EqEMFieldWithSpin ()
 

Private Attributes

G4double anomaly
 
G4double beta
 
G4double charge
 
G4double fElectroMagCof
 
G4double fMassCof
 
G4double gamma
 
G4Field * itsField = nullptr
 
G4double magMoment
 
G4double mass
 
G4double omegac
 
G4double spin
 

Detailed Description

Definition at line 43 of file G4EqEMFieldWithSpin.hh.

Constructor & Destructor Documentation

◆ G4EqEMFieldWithSpin()

G4EqEMFieldWithSpin::G4EqEMFieldWithSpin ( G4ElectroMagneticField *  emField)

Definition at line 38 of file G4EqEMFieldWithSpin.cc.

39 : G4EquationOfMotion( emField ), charge(0.), mass(0.), magMoment(0.),
40 spin(0.), fElectroMagCof(0.), fMassCof(0.), omegac(0.),
41 anomaly(0.0011659208), beta(0.), gamma(0.)
42{
43}
G4EquationOfMotion::G4EquationOfMotion
G4EquationOfMotion(G4Field *Field)
Definition: G4EquationOfMotion.cc:33

◆ ~G4EqEMFieldWithSpin()

G4EqEMFieldWithSpin::~G4EqEMFieldWithSpin ( )

Definition at line 45 of file G4EqEMFieldWithSpin.cc.

46{
47}

Member Function Documentation

◆ EvaluateRhsGivenB() [1/2]

virtual void G4EquationOfMotion::EvaluateRhsGivenB ( const G4double  y[],
const G4double  B[3],
G4double  dydx[] 
) const
pure virtualinherited

Implemented in G4ErrorMag_UsualEqRhs, G4Mag_SpinEqRhs, G4Mag_UsualEqRhs, G4KM_NucleonEqRhs, G4KM_OpticalEqRhs, and G4Mag_EqRhs.

Referenced by G4RKG3_Stepper::StepNoErr(), and G4RKG3_Stepper::Stepper().

◆ EvaluateRhsGivenB() [2/2]

void G4EqEMFieldWithSpin::EvaluateRhsGivenB ( const G4double  y[],
const G4double  Field[],
G4double  dydx[] 
) const

Definition at line 78 of file G4EqEMFieldWithSpin.cc.

81{
82
83 // Components of y:
84 // 0-2 dr/ds,
85 // 3-5 dp/ds - momentum derivatives
86 // 9-11 dSpin/ds = (1/beta) dSpin/dt - spin derivatives
87
88 // The BMT equation, following J.D.Jackson, Classical
89 // Electrodynamics, Second Edition,
90 // dS/dt = (e/mc) S \cross
91 // [ (g/2-1 +1/\gamma) B
92 // -(g/2-1)\gamma/(\gamma+1) (\beta \cdot B)\beta
93 // -(g/2-\gamma/(\gamma+1) \beta \cross E ]
94 // where
95 // S = \vec{s}, where S^2 = 1
96 // B = \vec{B}
97 // \beta = \vec{\beta} = \beta \vec{u} with u^2 = 1
98 // E = \vec{E}
99
100 G4double pSquared = y[3]*y[3] + y[4]*y[4] + y[5]*y[5] ;
101
102 G4double Energy = std::sqrt( pSquared + fMassCof );
103 G4double cof2 = Energy/c_light ;
104
105 G4double pModuleInverse = 1.0/std::sqrt(pSquared) ;
106
107 G4double inverse_velocity = Energy * pModuleInverse / c_light;
108
109 G4double cof1 = fElectroMagCof*pModuleInverse ;
110
111 dydx[0] = y[3]*pModuleInverse ;
112 dydx[1] = y[4]*pModuleInverse ;
113 dydx[2] = y[5]*pModuleInverse ;
114
115 dydx[3] = cof1*(cof2*Field[3] + (y[4]*Field[2] - y[5]*Field[1])) ;
116
117 dydx[4] = cof1*(cof2*Field[4] + (y[5]*Field[0] - y[3]*Field[2])) ;
118
119 dydx[5] = cof1*(cof2*Field[5] + (y[3]*Field[1] - y[4]*Field[0])) ;
120
121 dydx[6] = dydx[8] = 0.;//not used
122
123 // Lab Time of flight
124 dydx[7] = inverse_velocity;
125
126 G4ThreeVector BField(Field[0],Field[1],Field[2]);
127 G4ThreeVector EField(Field[3],Field[4],Field[5]);
128
129 EField /= c_light;
130
131 G4ThreeVector u(y[3], y[4], y[5]);
132 u *= pModuleInverse;
133
134 G4double udb = anomaly*beta*gamma/(1.+gamma) * (BField * u);
135 G4double ucb = (anomaly+1./gamma)/beta;
136 G4double uce = anomaly + 1./(gamma+1.);
137
138 G4ThreeVector Spin(y[9],y[10],y[11]);
139
140 G4double pcharge;
141 if (charge == 0.)
142 {
143 pcharge = 1.;
144 }
145 else
146 {
147 pcharge = charge;
148 }
149
150 G4ThreeVector dSpin(0.,0.,0.);
151 if (Spin.mag2() != 0.)
152 {
153 dSpin = pcharge*omegac*( ucb*(Spin.cross(BField))-udb*(Spin.cross(u))
154 // from Jackson
155 // -uce*Spin.cross(u.cross(EField)) );
156 // but this form has one less operation
157 - uce*(u*(Spin*EField) - EField*(Spin*u)) );
158 }
159
160 dydx[ 9] = dSpin.x();
161 dydx[10] = dSpin.y();
162 dydx[11] = dSpin.z();
163
164 return;
165}
G4double
double G4double
Definition: G4Types.hh:83
field_utils::Value3D::Spin
@ Spin
source.hepunit.c_light
float c_light
Definition: hepunit.py:256

References anomaly, beta, source.hepunit::c_light, charge, fElectroMagCof, fMassCof, gamma, omegac, CLHEP::Hep3Vector::x(), CLHEP::Hep3Vector::y(), and CLHEP::Hep3Vector::z().

◆ EvaluateRhsReturnB()

void G4EquationOfMotion::EvaluateRhsReturnB ( const G4double  y[],
G4double  dydx[],
G4double  Field[] 
) const
inlineinherited

Referenced by G4RKG3_Stepper::StepNoErr().

◆ GetAnomaly()

G4double G4EqEMFieldWithSpin::GetAnomaly ( ) const
inline

Definition at line 62 of file G4EqEMFieldWithSpin.hh.

62{ return anomaly; }

References anomaly.

◆ GetFieldObj() [1/2]

G4Field * G4EquationOfMotion::GetFieldObj ( )
inlineinherited

◆ GetFieldObj() [2/2]

const G4Field * G4EquationOfMotion::GetFieldObj ( ) const
inlineinherited

Referenced by G4NystromRK4::GetField().

◆ GetFieldValue()

void G4EquationOfMotion::GetFieldValue ( const G4double  Point[4],
G4double  Field[] 
) const
inlineinherited

Referenced by G4BFieldIntegrationDriver::GetFieldValue(), and G4MultiLevelLocator::ReportFieldValue().

◆ RightHandSide()

void G4EquationOfMotion::RightHandSide ( const G4double  y[],
G4double  dydx[] 
) const
inlineinherited

Referenced by G4ModifiedMidpoint::DoStep(), and G4VFSALIntegrationStepper::RightHandSide().

◆ SetAnomaly()

void G4EqEMFieldWithSpin::SetAnomaly ( G4double  a)
inline

Definition at line 61 of file G4EqEMFieldWithSpin.hh.

61{ anomaly = a; }

References anomaly.

◆ SetChargeMomentumMass()

void G4EqEMFieldWithSpin::SetChargeMomentumMass ( G4ChargeState  particleCharge,
G4double  MomentumXc,
G4double  mass 
)
virtual

Implements G4EquationOfMotion.

Definition at line 50 of file G4EqEMFieldWithSpin.cc.

53{
54 charge = particleCharge.GetCharge();
55 mass = particleMass;
56 magMoment = particleCharge.GetMagneticDipoleMoment();
57 spin = particleCharge.GetSpin();
58
59 fElectroMagCof = eplus*charge*c_light ;
60 fMassCof = mass*mass;
61
62 omegac = (eplus/mass)*c_light;
63
64 G4double muB = 0.5*eplus*hbar_Planck/(mass/c_squared);
65
66 G4double g_BMT;
67 if ( spin != 0. ) g_BMT = (std::abs(magMoment)/muB)/spin;
68 else g_BMT = 2.;
69
70 anomaly = (g_BMT - 2.)/2.;
71
72 G4double E = std::sqrt(sqr(MomentumXc)+sqr(mass));
73 beta = MomentumXc/E;
74 gamma = E/mass;
75}
eplus
static constexpr double eplus
Definition: G4SIunits.hh:184
G4ChargeState::GetCharge
G4double GetCharge() const
Definition: G4ChargeState.hh:61
G4ChargeState::GetMagneticDipoleMoment
G4double GetMagneticDipoleMoment() const
Definition: G4ChargeState.hh:71
G4ChargeState::GetSpin
G4double GetSpin() const
Definition: G4ChargeState.hh:105
source.hepunit.hbar_Planck
float hbar_Planck
Definition: hepunit.py:263
source.hepunit.c_squared
float c_squared
Definition: hepunit.py:257
sqr
T sqr(const T &x)
Definition: templates.hh:128

References anomaly, beta, source.hepunit::c_light, source.hepunit::c_squared, charge, eplus, fElectroMagCof, fMassCof, gamma, G4ChargeState::GetCharge(), G4ChargeState::GetMagneticDipoleMoment(), G4ChargeState::GetSpin(), source.hepunit::hbar_Planck, magMoment, mass, omegac, spin, and sqr().

◆ SetFieldObj()

void G4EquationOfMotion::SetFieldObj ( G4Field *  pField)
inlineinherited

Referenced by G4FieldManager::SetDetectorField(), and G4NystromRK4::SetDistanceForConstantField().

Field Documentation

◆ anomaly

G4double G4EqEMFieldWithSpin::anomaly
private

Definition at line 72 of file G4EqEMFieldWithSpin.hh.

Referenced by EvaluateRhsGivenB(), GetAnomaly(), SetAnomaly(), and SetChargeMomentumMass().

◆ beta

G4double G4EqEMFieldWithSpin::beta
private

Definition at line 73 of file G4EqEMFieldWithSpin.hh.

Referenced by EvaluateRhsGivenB(), and SetChargeMomentumMass().

◆ charge

G4double G4EqEMFieldWithSpin::charge
private

Definition at line 67 of file G4EqEMFieldWithSpin.hh.

Referenced by EvaluateRhsGivenB(), and SetChargeMomentumMass().

◆ fElectroMagCof

G4double G4EqEMFieldWithSpin::fElectroMagCof
private

Definition at line 69 of file G4EqEMFieldWithSpin.hh.

Referenced by EvaluateRhsGivenB(), and SetChargeMomentumMass().

◆ fMassCof

G4double G4EqEMFieldWithSpin::fMassCof
private

Definition at line 70 of file G4EqEMFieldWithSpin.hh.

Referenced by EvaluateRhsGivenB(), and SetChargeMomentumMass().

◆ gamma

G4double G4EqEMFieldWithSpin::gamma
private

Definition at line 73 of file G4EqEMFieldWithSpin.hh.

Referenced by EvaluateRhsGivenB(), and SetChargeMomentumMass().

◆ itsField

G4Field* G4EquationOfMotion::itsField = nullptr
privateinherited

Definition at line 90 of file G4EquationOfMotion.hh.

◆ magMoment

G4double G4EqEMFieldWithSpin::magMoment
private

Definition at line 67 of file G4EqEMFieldWithSpin.hh.

Referenced by SetChargeMomentumMass().

◆ mass

G4double G4EqEMFieldWithSpin::mass
private

Definition at line 67 of file G4EqEMFieldWithSpin.hh.

Referenced by SetChargeMomentumMass().

◆ omegac

G4double G4EqEMFieldWithSpin::omegac
private

Definition at line 72 of file G4EqEMFieldWithSpin.hh.

Referenced by EvaluateRhsGivenB(), and SetChargeMomentumMass().

◆ spin

G4double G4EqEMFieldWithSpin::spin
private

Definition at line 67 of file G4EqEMFieldWithSpin.hh.

Referenced by SetChargeMomentumMass().

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