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25 //
26 /// \file exoticphysics/monopole/src/G4MonopoleEquation.cc
27 /// \brief Implementation of the G4MonopoleEquation class
28 //
29 //
30 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
31 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
32 //
33 //
34 // class G4MonopoleEquation
35 //
36 // Class description:
37 //
38 //
39 // This is the standard right-hand side for equation of motion.
40 //
41 // The only case another is required is when using a moving reference
42 // frame ... or extending the class to include additional Forces,
43 // eg an electric field
44 //
45 // 10.11.98 V.Grichine
46 //
47 // 30.04.10 S.Burdin (modified to use for the monopole trajectories).
48 //
49 // 15.06.10 B.Bozsogi (replaced the hardcoded magnetic charge with
50 // the one passed by G4MonopoleTransportation)
51 // +workaround to pass the electric charge.
52 //
53 // 12.07.10 S.Burdin (added equations for the electric charges)
54 // -------------------------------------------------------------------
55
56 #include "G4MonopoleEquation.hh"
57
58 #include "G4PhysicalConstants.hh"
59 #include "G4SystemOfUnits.hh"
60 #include "globals.hh"
61
62 #include <iomanip>
63
64 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
65
66 G4MonopoleEquation::G4MonopoleEquation(G4MagneticField* emField) : G4EquationOfMotion(emField)
67 {
68 G4cout << "G4MonopoleEquation::G4MonopoleEquation" << G4endl;
69 }
70
71 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
72
73 G4MonopoleEquation::~G4MonopoleEquation() {}
74
75 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
76
77 void G4MonopoleEquation::SetChargeMomentumMass(G4ChargeState particleChargeState,
78 G4double, // momentum,
79 G4double particleMass)
80 {
81 G4double particleMagneticCharge = particleChargeState.MagneticCharge();
82 G4double particleElectricCharge = particleChargeState.GetCharge();
83
84 // fElCharge = particleElectricCharge;
85 fElCharge = eplus * particleElectricCharge * c_light;
86
87 fMagCharge = eplus * particleMagneticCharge * c_light;
88
89 // G4cout << " G4MonopoleEquation: ElectricCharge=" << particleElectricCharge
90 // << "; MagneticCharge=" << particleMagneticCharge
91 // << G4endl;
92
93 fMassCof = particleMass * particleMass;
94 }
95
96 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
97
98 void G4MonopoleEquation::EvaluateRhsGivenB(const G4double y[], const G4double Field[],
99 G4double dydx[]) const
100 {
101 // Components of y:
102 // 0-2 dr/ds,
103 // 3-5 dp/ds - momentum derivatives
104
105 G4double pSquared = y[3] * y[3] + y[4] * y[4] + y[5] * y[5];
106
107 G4double Energy = std::sqrt(pSquared + fMassCof);
108
109 G4double pModuleInverse = 1.0 / std::sqrt(pSquared);
110
111 G4double inverse_velocity = Energy * pModuleInverse / c_light;
112
113 G4double cofEl = fElCharge * pModuleInverse;
114 G4double cofMag = fMagCharge * Energy * pModuleInverse;
115
116 dydx[0] = y[3] * pModuleInverse;
117 dydx[1] = y[4] * pModuleInverse;
118 dydx[2] = y[5] * pModuleInverse;
119
120 // G4double magCharge = twopi * hbar_Planck / (eplus * mu0);
121 // magnetic charge in SI units A*m convention
122 // see http://en.wikipedia.org/wiki/Magnetic_monopole
123 // G4cout << "Magnetic charge: " << magCharge << G4endl;
124 // dp/ds = dp/dt * dt/ds = dp/dt / v = Force / velocity
125 // dydx[3] = fMagCharge * Field[0] * inverse_velocity * c_light;
126 // multiplied by c_light to convert to MeV/mm
127 // dydx[4] = fMagCharge * Field[1] * inverse_velocity * c_light;
128 // dydx[5] = fMagCharge * Field[2] * inverse_velocity * c_light;
129
130 dydx[3] = cofMag * Field[0] + cofEl * (y[4] * Field[2] - y[5] * Field[1]);
131 dydx[4] = cofMag * Field[1] + cofEl * (y[5] * Field[0] - y[3] * Field[2]);
132 dydx[5] = cofMag * Field[2] + cofEl * (y[3] * Field[1] - y[4] * Field[0]);
133
134 // G4cout << std::setprecision(5)<< "E=" << Energy
135 // << "; p="<< 1/pModuleInverse
136 // << "; mC="<< magCharge
137 // <<"; x=" << y[0]
138 // <<"; y=" << y[1]
139 // <<"; z=" << y[2]
140 // <<"; dydx[3]=" << dydx[3]
141 // <<"; dydx[4]=" << dydx[4]
142 // <<"; dydx[5]=" << dydx[5]
143 // << G4endl;
144
145 dydx[6] = 0.; // not used
146
147 // Lab Time of flight
148 dydx[7] = inverse_velocity;
149 return;
150 }
151
152 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
153