G4Mag_SpinEqRhs Class Reference

#include <G4Mag_SpinEqRhs.hh>

Inheritance diagram for G4Mag_SpinEqRhs:

G4Mag_EqRhs G4EquationOfMotion

Public Member Functions

 G4Mag_SpinEqRhs (G4MagneticField *MagField)
 ~G4Mag_SpinEqRhs ()
void SetChargeMomentumMass (G4double particleCharge, G4double MomentumXc, G4double mass)
void EvaluateRhsGivenB (const G4double y[], const G4double B[3], G4double dydx[]) const
void SetAnomaly (G4double a)
G4double GetAnomaly () const

Detailed Description

Definition at line 50 of file G4Mag_SpinEqRhs.hh.


Constructor & Destructor Documentation

G4Mag_SpinEqRhs::G4Mag_SpinEqRhs ( G4MagneticField MagField  ) 

Definition at line 45 of file G4Mag_SpinEqRhs.cc.

00046   : G4Mag_EqRhs( MagField ), omegac(0.), anomaly(0.0011659208),
00047     pcharge(0.), E(0.), gamma(0.), beta(0.)
00048 {
00049 }

G4Mag_SpinEqRhs::~G4Mag_SpinEqRhs (  ) 

Definition at line 51 of file G4Mag_SpinEqRhs.cc.

00052 {
00053 }


Member Function Documentation

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

Implements G4Mag_EqRhs.

Definition at line 76 of file G4Mag_SpinEqRhs.cc.

References G4Mag_EqRhs::FCof(), and sqr().

00079 {
00080    G4double momentum_mag_square = sqr(y[3]) + sqr(y[4]) + sqr(y[5]);
00081    G4double inv_momentum_magnitude = 1.0 / std::sqrt( momentum_mag_square );
00082    G4double cof = FCof()*inv_momentum_magnitude;
00083 
00084    dydx[0] = y[3] * inv_momentum_magnitude;       //  (d/ds)x = Vx/V
00085    dydx[1] = y[4] * inv_momentum_magnitude;       //  (d/ds)y = Vy/V
00086    dydx[2] = y[5] * inv_momentum_magnitude;       //  (d/ds)z = Vz/V
00087 
00088    if (pcharge == 0.) {
00089       dydx[3] = 0.;
00090       dydx[4] = 0.;
00091       dydx[5] = 0.;
00092    } else {
00093       dydx[3] = cof*(y[4]*B[2] - y[5]*B[1]) ;   // Ax = a*(Vy*Bz - Vz*By)
00094       dydx[4] = cof*(y[5]*B[0] - y[3]*B[2]) ;   // Ay = a*(Vz*Bx - Vx*Bz)
00095       dydx[5] = cof*(y[3]*B[1] - y[4]*B[0]) ;   // Az = a*(Vx*By - Vy*Bx)
00096    }
00097 
00098    G4ThreeVector u(y[3], y[4], y[5]);
00099    u *= inv_momentum_magnitude; 
00100 
00101    G4ThreeVector BField(B[0],B[1],B[2]);
00102 
00103    G4double udb = anomaly*beta*gamma/(1.+gamma) * (BField * u); 
00104    G4double ucb = (anomaly+1./gamma)/beta;
00105 
00106    // Initialise the values of dydx that we do not update.
00107    dydx[6] = dydx[7] = dydx[8] = 0.0;
00108 
00109    G4ThreeVector Spin(y[9],y[10],y[11]);
00110 
00111    G4ThreeVector dSpin;
00112 
00113    if (pcharge == 0.) {
00114       // dSpin = (3.8260837/2.)*omegac*(Spin.cross(BField));
00115       dSpin = omegac*(ucb*(Spin.cross(BField))-udb*(Spin.cross(u)));
00116    } else {
00117       dSpin = pcharge*omegac*(ucb*(Spin.cross(BField))-udb*(Spin.cross(u)));
00118    }
00119 
00120    dydx[ 9] = dSpin.x();
00121    dydx[10] = dSpin.y();
00122    dydx[11] = dSpin.z();
00123 
00124    return ;
00125 }

G4double G4Mag_SpinEqRhs::GetAnomaly (  )  const [inline]

Definition at line 69 of file G4Mag_SpinEqRhs.hh.

00069 { return anomaly; }

void G4Mag_SpinEqRhs::SetAnomaly ( G4double  a  )  [inline]

Definition at line 68 of file G4Mag_SpinEqRhs.hh.

Referenced by SetChargeMomentumMass().

00068 { anomaly = a; }

void G4Mag_SpinEqRhs::SetChargeMomentumMass ( G4double  particleCharge,
G4double  MomentumXc,
G4double  mass 
) [virtual]

Reimplemented from G4Mag_EqRhs.

Definition at line 56 of file G4Mag_SpinEqRhs.cc.

References SetAnomaly(), G4Mag_EqRhs::SetChargeMomentumMass(), and sqr().

00059 {
00060    //  To set fCof_val 
00061    G4Mag_EqRhs::SetChargeMomentumMass(particleCharge, MomentumXc, particleMass);
00062 
00063    omegac = (eplus/particleMass)*c_light;
00064 
00065    pcharge = particleCharge;
00066 
00067    E = std::sqrt(sqr(MomentumXc)+sqr(particleMass));
00068    beta  = MomentumXc/E;
00069    gamma = E/particleMass;
00070 
00071    G4double neutronAnomaly = -2.9156797;
00072    if (pcharge==0.) SetAnomaly(neutronAnomaly);
00073 }


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