Geant4  10.02
G4EqMagElectricField.cc
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27 // $Id: G4EqMagElectricField.cc 69699 2013-05-13 08:50:30Z gcosmo $
28 //
29 //
30 // This is the standard right-hand side for equation of motion.
31 //
32 // The only case another is required is when using a moving reference
33 // frame ... or extending the class to include additional Forces,
34 // eg an electric field
35 //
36 // 10.11.98 V.Grichine
37 //
38 // -------------------------------------------------------------------
39 
40 #include "G4EqMagElectricField.hh"
41 #include "globals.hh"
42 #include "G4PhysicalConstants.hh"
43 #include "G4SystemOfUnits.hh"
44 
45 void
47  G4double,
48  G4double particleMass)
49 {
50  G4double pcharge = particleCharge.GetCharge();
51  fElectroMagCof = eplus*pcharge*c_light ;
52  fMassCof = particleMass*particleMass ;
53 }
54 
55 
56 
57 void
59  const G4double Field[],
60  G4double dydx[] ) const
61 {
62 
63  // Components of y:
64  // 0-2 dr/ds,
65  // 3-5 dp/ds - momentum derivatives
66 
67  G4double pSquared = y[3]*y[3] + y[4]*y[4] + y[5]*y[5] ;
68 
69  G4double Energy = std::sqrt( pSquared + fMassCof );
70  G4double cof2 = Energy/c_light ;
71 
72  G4double pModuleInverse = 1.0/std::sqrt(pSquared) ;
73 
74  // G4double inverse_velocity = Energy * c_light * pModuleInverse;
75  G4double inverse_velocity = Energy * pModuleInverse / c_light;
76 
77  G4double cof1 = fElectroMagCof*pModuleInverse ;
78 
79  // G4double vDotE = y[3]*Field[3] + y[4]*Field[4] + y[5]*Field[5] ;
80 
81 
82  dydx[0] = y[3]*pModuleInverse ;
83  dydx[1] = y[4]*pModuleInverse ;
84  dydx[2] = y[5]*pModuleInverse ;
85 
86  dydx[3] = cof1*(cof2*Field[3] + (y[4]*Field[2] - y[5]*Field[1])) ;
87 
88  dydx[4] = cof1*(cof2*Field[4] + (y[5]*Field[0] - y[3]*Field[2])) ;
89 
90  dydx[5] = cof1*(cof2*Field[5] + (y[3]*Field[1] - y[4]*Field[0])) ;
91 
92  dydx[6] = 0.;//not used
93 
94  // Lab Time of flight
95  dydx[7] = inverse_velocity;
96  return ;
97 }
G4double GetCharge() const
void SetChargeMomentumMass(G4ChargeState particleCharge, G4double MomentumXc, G4double mass)
double G4double
Definition: G4Types.hh:76
static const double eplus
Definition: G4SIunits.hh:196
void EvaluateRhsGivenB(const G4double y[], const G4double Field[], G4double dydx[]) const