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G4KM_OpticalEqRhs.cc
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28 // GEANT 4 class implementation file
29 //
30 // CERN, Geneva, Switzerland
31 //
32 // File name: G4KM_OpticalEqRhs.cc
33 //
34 // Author: Alessandro Brunengo (Alessandro.Brunengo@ge.infn.it)
35 //
36 // Creation date: 5 June 2000
37 // -------------------------------------------------------------------
38 
39 #include "G4KM_OpticalEqRhs.hh"
40 #include "G4PhysicalConstants.hh"
41 #include "G4NucleiProperties.hh"
42 #include "G4VNuclearDensity.hh"
43 #include "G4HadTmpUtil.hh"
44 
46  G4V3DNucleus * nucleus) :
47  G4Mag_EqRhs(field), theNucleus(nucleus)
48 {
49  theFactor = 0;
50  theMass = 0;
51 }
52 
53 
54 void G4KM_OpticalEqRhs::SetFactor(G4double mass, G4double opticalParameter)
55 {
56  G4double A = theNucleus->GetMassNumber();
57  G4double Z = theNucleus->GetCharge();
59  G4double nucleusMass = Z*proton_mass_c2+(A-Z)*neutron_mass_c2+bindingEnergy;
60  G4double reducedMass = mass*nucleusMass/(mass+nucleusMass);
61 
62  G4double nucleonMass = (proton_mass_c2+neutron_mass_c2)/2;
63 
64 // _factor in (MeV*fermi)*fermi/MeV = fermi*fermi -- need to have A as density normalized to 1
65  theFactor = 2*pi*hbarc*hbarc*(1+mass/nucleonMass)* opticalParameter/reducedMass * A;
66 
67  theMass = mass;
68 }
69 
70 
72  G4double dydx[]) const
73 {
74  G4double yMod = std::sqrt(y[0]*y[0]+y[1]*y[1]+y[2]*y[2]);
75  G4double e = std::sqrt(theMass*theMass+y[3]*y[3]+y[4]*y[4]+y[5]*y[5]);
76  dydx[0] = c_light*y[3]/e; //
77  dydx[1] = c_light*y[4]/e; // dq/dt=dH/dp = c*p/e
78  dydx[2] = c_light*y[5]/e; //
79 
80 // V=K*rho(r) ==> dydx[3] = -dV/dr*dr/dx = -K*d(rho)/dr*dr/dx.
81 // Idem for dydx[4] and dydx[5]
82 
83  const G4VNuclearDensity * nuclearDensity=theNucleus->GetNuclearDensity();
84 
85  G4ThreeVector pos(y[0],y[1],y[2]);
86  G4double deriv = theFactor*nuclearDensity->GetDeriv(pos);
87 
88  dydx[3] = yMod == 0 ? 0 : -deriv*y[0]/yMod*c_light;
89  dydx[4] = yMod == 0 ? 0 : -deriv*y[1]/yMod*c_light;
90  dydx[5] = yMod == 0 ? 0 : -deriv*y[2]/yMod*c_light;
91 }
92 
93 // Here by design, but it is unnecessary for nuclear fields
95 {
96 }
virtual G4int GetCharge()=0
virtual const G4VNuclearDensity * GetNuclearDensity() const =0
virtual G4int GetMassNumber()=0
virtual void EvaluateRhsGivenB(const G4double y[], const G4double B[3], G4double dydx[]) const
G4KM_OpticalEqRhs(G4KM_DummyField *field, G4V3DNucleus *nucleus)
double A(double temperature)
float proton_mass_c2
Definition: hepunit.py:275
virtual G4double GetDeriv(const G4ThreeVector &point) const =0
float neutron_mass_c2
Definition: hepunit.py:276
virtual void SetChargeMomentumMass(G4ChargeState particleCharge, G4double MomentumXc, G4double MassXc2)
static G4double GetBindingEnergy(const G4int A, const G4int Z)
int G4lrint(double ad)
Definition: templates.hh:163
void SetFactor(G4double mass, G4double opticalParameter)
static constexpr double pi
Definition: G4SIunits.hh:75
double G4double
Definition: G4Types.hh:76
G4double bindingEnergy(G4int A, G4int Z)
float c_light
Definition: hepunit.py:257
static const G4double pos