Geant4 11.2.2
Toolkit for the simulation of the passage of particles through matter
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G4EqGravityField.cc
Go to the documentation of this file.
1//
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25//
26// G4EqGravityField implementation
27//
28// This is the right-hand side for equation of motion for a
29// massive particle in a gravitational field.
30//
31// Created: P.Gumplinger, 14.06.11 - Adopted from G4EqMagElectricField
32// Thanks to P.Fierlinger (PSI) and A.Capra and A.Fontana (INFN Pavia)
33// -------------------------------------------------------------------
34
35#include "G4EqGravityField.hh"
36#include "globals.hh"
38
43
45
46void
49 G4double particleMass )
50{
51 fMass = particleMass;
52}
53
54void
56 const G4double G[],
57 G4double dydx[] ) const
58{
59
60 // Components of y:
61 // 0-2 dr/ds,
62 // 3-5 dp/ds - momentum derivatives
63
64 G4double momentum_mag_square = y[3]*y[3] + y[4]*y[4] + y[5]*y[5];
65 G4double inv_momentum_magnitude = 1.0 / std::sqrt( momentum_mag_square );
66
67 G4double Energy = std::sqrt(momentum_mag_square + fMass*fMass);
68 G4double cof2 = Energy/c_light;
69 G4double cof1 = inv_momentum_magnitude*fMass;
70 G4double inverse_velocity = Energy*inv_momentum_magnitude/c_light;
71
72 dydx[0] = y[3]*inv_momentum_magnitude; // (d/ds)x = Vx/V
73 dydx[1] = y[4]*inv_momentum_magnitude; // (d/ds)y = Vy/V
74 dydx[2] = y[5]*inv_momentum_magnitude; // (d/ds)z = Vz/V
75
76 dydx[3] = G[0]*cof1*cof2/c_light;
77 dydx[4] = G[1]*cof1*cof2/c_light; // m*g
78 dydx[5] = G[2]*cof1*cof2/c_light;
79
80 // Lab Time of flight
81 //
82 dydx[7] = inverse_velocity;
83
84 return;
85}
double G4double
Definition G4Types.hh:83
void EvaluateRhsGivenB(const G4double y[], const G4double Field[], G4double dydx[]) const override
void SetChargeMomentumMass(G4ChargeState particleCharge, G4double MomentumXc, G4double mass) override
G4EqGravityField(G4UniformGravityField *gField)
~G4EqGravityField() override