Geant4  10.03.p01
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G4Mag_SpinEqRhs Class Reference

#include <G4Mag_SpinEqRhs.hh>

Inheritance diagram for G4Mag_SpinEqRhs:
Collaboration diagram for G4Mag_SpinEqRhs:

Public Member Functions

 G4Mag_SpinEqRhs (G4MagneticField *MagField)
 
 ~G4Mag_SpinEqRhs ()
 
void SetChargeMomentumMass (G4ChargeState particleCharge, G4double MomentumXc, G4double mass)
 
void EvaluateRhsGivenB (const G4double y[], const G4double B[3], G4double dydx[]) const
 
void SetAnomaly (G4double a)
 
G4double GetAnomaly () const
 
- Public Member Functions inherited from G4Mag_EqRhs
 G4Mag_EqRhs (G4MagneticField *magField)
 
virtual ~G4Mag_EqRhs ()
 
G4double FCof () const
 
- Public Member Functions inherited from G4EquationOfMotion
 G4EquationOfMotion (G4Field *Field)
 
virtual ~G4EquationOfMotion ()
 
void RightHandSide (const G4double y[], G4double dydx[]) const
 
void EvaluateRhsReturnB (const G4double y[], G4double dydx[], G4double Field[]) const
 
void GetFieldValue (const G4double Point[4], G4double Field[]) const
 
const G4FieldGetFieldObj () const
 
void SetFieldObj (G4Field *pField)
 

Detailed Description

Definition at line 51 of file G4Mag_SpinEqRhs.hh.

Constructor & Destructor Documentation

G4Mag_SpinEqRhs::G4Mag_SpinEqRhs ( G4MagneticField MagField)

Definition at line 45 of file G4Mag_SpinEqRhs.cc.

46  : G4Mag_EqRhs( MagField ), charge(0.), mass(0.), magMoment(0.),
47  spin(0.), omegac(0.), anomaly(0.0011659208), beta(0.), gamma(0.)
48 {
49 }
G4Mag_EqRhs(G4MagneticField *magField)
Definition: G4Mag_EqRhs.cc:50
G4Mag_SpinEqRhs::~G4Mag_SpinEqRhs ( )

Definition at line 51 of file G4Mag_SpinEqRhs.cc.

52 {
53 }

Member Function Documentation

void G4Mag_SpinEqRhs::EvaluateRhsGivenB ( const G4double  y[],
const G4double  B[3],
G4double  dydx[] 
) const
virtual

Implements G4Mag_EqRhs.

Definition at line 83 of file G4Mag_SpinEqRhs.cc.

86 {
87  G4double momentum_mag_square = sqr(y[3]) + sqr(y[4]) + sqr(y[5]);
88  G4double inv_momentum_magnitude = 1.0 / std::sqrt( momentum_mag_square );
89  G4double cof = FCof()*inv_momentum_magnitude;
90 
91  dydx[0] = y[3] * inv_momentum_magnitude; // (d/ds)x = Vx/V
92  dydx[1] = y[4] * inv_momentum_magnitude; // (d/ds)y = Vy/V
93  dydx[2] = y[5] * inv_momentum_magnitude; // (d/ds)z = Vz/V
94 
95  if (charge == 0.) {
96  dydx[3] = 0.;
97  dydx[4] = 0.;
98  dydx[5] = 0.;
99  } else {
100  dydx[3] = cof*(y[4]*B[2] - y[5]*B[1]) ; // Ax = a*(Vy*Bz - Vz*By)
101  dydx[4] = cof*(y[5]*B[0] - y[3]*B[2]) ; // Ay = a*(Vz*Bx - Vx*Bz)
102  dydx[5] = cof*(y[3]*B[1] - y[4]*B[0]) ; // Az = a*(Vx*By - Vy*Bx)
103  }
104 
105  G4ThreeVector u(y[3], y[4], y[5]);
106  u *= inv_momentum_magnitude;
107 
108  G4ThreeVector BField(B[0],B[1],B[2]);
109 
110  G4double udb = anomaly*beta*gamma/(1.+gamma) * (BField * u);
111  G4double ucb = (anomaly+1./gamma)/beta;
112 
113  // Initialise the values of dydx that we do not update.
114  dydx[6] = dydx[7] = dydx[8] = 0.0;
115 
116  G4ThreeVector Spin(y[9],y[10],y[11]);
117 
118  G4double pcharge;
119  if (charge == 0.) pcharge = 1.;
120  else pcharge = charge;
121 
122  G4ThreeVector dSpin(0.,0.,0.);
123  if (Spin.mag2() != 0.) {
124  dSpin = pcharge*omegac*(ucb*(Spin.cross(BField))-udb*(Spin.cross(u)));
125  }
126 
127  dydx[ 9] = dSpin.x();
128  dydx[10] = dSpin.y();
129  dydx[11] = dSpin.z();
130 
131  return ;
132 }
double B(double temperature)
G4double FCof() const
Definition: G4Mag_EqRhs.hh:84
T sqr(const T &x)
Definition: templates.hh:145
double G4double
Definition: G4Types.hh:76

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G4double G4Mag_SpinEqRhs::GetAnomaly ( ) const
inline

Definition at line 70 of file G4Mag_SpinEqRhs.hh.

70 { return anomaly; }
void G4Mag_SpinEqRhs::SetAnomaly ( G4double  a)
inline

Definition at line 69 of file G4Mag_SpinEqRhs.hh.

69 { anomaly = a; }
void G4Mag_SpinEqRhs::SetChargeMomentumMass ( G4ChargeState  particleCharge,
G4double  MomentumXc,
G4double  mass 
)
virtual

Reimplemented from G4Mag_EqRhs.

Definition at line 56 of file G4Mag_SpinEqRhs.cc.

59 {
60  G4Mag_EqRhs::SetChargeMomentumMass( particleCharge, MomentumXc, mass);
61 
62  charge = particleCharge.GetCharge();
63  mass = particleMass;
64  magMoment = particleCharge.GetMagneticDipoleMoment();
65  spin = particleCharge.GetSpin();
66 
67  omegac = (eplus/mass)*c_light;
68 
69  G4double muB = 0.5*eplus*hbar_Planck/(mass/c_squared);
70 
71  G4double g_BMT;
72  if ( spin != 0. ) g_BMT = (std::abs(magMoment)/muB)/spin;
73  else g_BMT = 2.;
74 
75  anomaly = (g_BMT - 2.)/2.;
76 
77  G4double E = std::sqrt(sqr(MomentumXc)+sqr(mass));
78  beta = MomentumXc/E;
79  gamma = E/mass;
80 }
G4double GetCharge() const
static constexpr double eplus
Definition: G4SIunits.hh:199
virtual void SetChargeMomentumMass(G4ChargeState particleCharge, G4double MomentumXc, G4double mass)
Definition: G4Mag_EqRhs.cc:56
static constexpr double c_squared
static constexpr double c_light
G4double GetSpin() const
G4double GetMagneticDipoleMoment() const
T sqr(const T &x)
Definition: templates.hh:145
double G4double
Definition: G4Types.hh:76
static constexpr double hbar_Planck

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