Geant4_10
G4KM_NucleonEqRhs.cc
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28 // GEANT 4 class implementation file
29 //
30 // CERN, Geneva, Switzerland
31 //
32 // File name: G4KM_NucleonEqRhs.cc
33 //
34 // Author: Alessandro Brunengo (Alessandro.Brunengo@ge.infn.it)
35 //
36 // Creation date: 5 June 2000
37 // -------------------------------------------------------------------
38 
39 #include "G4KM_NucleonEqRhs.hh"
40 #include "G4VNuclearDensity.hh"
41 
42 #include "G4PhysicalConstants.hh"
43 
45  G4V3DNucleus * nucleus) :
46  G4Mag_EqRhs(field), theNucleus(nucleus)
47 {
48  theMass = 0.;
49  A = theNucleus->GetMassNumber();
50  factor = hbarc*hbarc*std::pow(3.*pi2*A,2./3.)/3.;
51 }
52 
53 
55  const G4double *,
56  G4double dydx[]) const
57 {
58  G4double yMod = std::sqrt(y[0]*y[0]+y[1]*y[1]+y[2]*y[2]);
59  G4double e = std::sqrt(theMass*theMass+y[3]*y[3]+y[4]*y[4]+y[5]*y[5]);
60 
61 // y[0..2] is position
62 // y[3..5] is momentum (and not mom.direction)
63 
64  dydx[0] = c_light*y[3]/e; //
65  dydx[1] = c_light*y[4]/e; // dq/dt=dH/dp = c*p/e
66  dydx[2] = c_light*y[5]/e; //
67 
68 /*
69  * // debug
70  * G4cout << " Nucleon RHS : 0..2(dpos/dt) " <<
71  * dydx[0] << " " <<
72  * dydx[1] << " " <<
73  * dydx[2] << " " << G4endl;
74  */
75 
76 
77 // V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dx.
78 // GF should be V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dt
79 // GF and dV/dt = dE/dt ==> dp/dt = dE/dt * dp/dE = dE/dt *e/p
80 // Idem for dydx[4] and dydx[5]
81 
82  G4ThreeVector pos(y[0],y[1],y[2]);
83 
84  const G4VNuclearDensity * nuclearDensity=theNucleus->GetNuclearDensity();
85 
86 // do not check for theMass != 0 : it is an error and core dump will signal it
87 
88  G4double density= nuclearDensity->GetDensity(pos);
89  G4double deriv(0);
90  if (density > 0 ) deriv = (factor/theMass)*
91  std::pow(density, -1./3.)*nuclearDensity->GetDeriv(pos);
92 
93 // dydx[3] = yMod == 0 ? 0 : -deriv*y[0]/yMod;
94 // dydx[4] = yMod == 0 ? 0 : -deriv*y[1]/yMod;
95 // dydx[5] = yMod == 0 ? 0 : -deriv*y[2]/yMod;
96  dydx[3] = yMod == 0 ? 0 : deriv*y[0]/yMod*c_light;
97  dydx[4] = yMod == 0 ? 0 : deriv*y[1]/yMod*c_light;
98  dydx[5] = yMod == 0 ? 0 : deriv*y[2]/yMod*c_light;
99 
100 
101 /*
102  * // debug
103  * G4cout << " Nucleon RHS : 3..5(dE/dt) " <<
104  * dydx[3] << " " <<
105  * dydx[4] << " " <<
106  * dydx[5] << " " << G4endl;
107  */
108 }
109 
110 // Here by design, but it is unnecessary for nuclear fields
112 {
113 }
virtual const G4VNuclearDensity * GetNuclearDensity() const =0
virtual G4int GetMassNumber()=0
virtual void SetChargeMomentumMass(G4ChargeState particleCharge, G4double MomentumXc, G4double MassXc2)
Double_t y
Definition: plot.C:279
G4double density
Definition: TRTMaterials.hh:39
virtual G4double GetDeriv(const G4ThreeVector &point) const =0
G4double GetDensity(const G4ThreeVector &aPosition) const
virtual void EvaluateRhsGivenB(const G4double y[], const G4double B[3], G4double dydx[]) const
double G4double
Definition: G4Types.hh:76
G4KM_NucleonEqRhs(G4KM_DummyField *field, G4V3DNucleus *nucleus)
float c_light
Definition: hepunit.py:257