1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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16 | // * for the full disclaimer and the limitation of liability. * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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22 | // * use in resulting scientific publications, and indicate your * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4MonopoleEq.cc,v 1.2 2010/03/18 10:23:29 japost Exp $ |
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28 | // GEANT4 tag $Name: field-V09-03-03 $ |
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29 | // |
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30 | // |
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31 | // This is the right-hand side for equation of motion for a |
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32 | // magnetic charge in a combined Electro-Magnetic field |
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33 | // |
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34 | // d(p_c)/ds=g{c-energyB_ - p_c x E}/pc |
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35 | // |
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36 | // 17.11.09 V.Grichine |
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37 | // |
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38 | // ------------------------------------------------------------------- |
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39 | |
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40 | #include "G4MonopoleEq.hh" |
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41 | #include "globals.hh" |
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42 | |
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43 | void |
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44 | G4MonopoleEq::SetChargeMomentumMass(G4double particleCharge, // e+ units |
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45 | G4double, |
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46 | G4double particleMass) |
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47 | { |
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48 | fElectroMagCof = eplus*particleCharge; // no *c_light as for ususal q |
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49 | fElectroMagCof /= 2*fine_structure_const; |
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50 | |
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51 | fMassCof = particleMass*particleMass ; |
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52 | } |
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53 | |
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54 | |
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55 | |
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56 | void |
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57 | G4MonopoleEq::EvaluateRhsGivenB(const G4double y[], |
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58 | const G4double Field[], |
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59 | G4double dydx[] ) const |
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60 | { |
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61 | |
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62 | // Components of y: |
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63 | // 0-2 dr/ds, |
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64 | // 3-5 d(pc)/ds - momentum derivatives |
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65 | |
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66 | G4double pSquared = y[3]*y[3] + y[4]*y[4] + y[5]*y[5] ; |
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67 | |
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68 | G4double Energy = std::sqrt( pSquared + fMassCof ); |
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69 | G4double cof2 = Energy*c_light ; |
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70 | |
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71 | G4double pModuleInverse = 1.0/std::sqrt(pSquared) ; |
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72 | |
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73 | // G4double inverse_velocity = Energy * c_light * pModuleInverse; |
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74 | G4double inverse_velocity = Energy * pModuleInverse / c_light; |
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75 | |
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76 | G4double cof1 = fElectroMagCof*pModuleInverse ; |
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77 | |
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78 | // G4double vDotE = y[3]*Field[3] + y[4]*Field[4] + y[5]*Field[5] ; |
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79 | |
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80 | dydx[0] = y[3]*pModuleInverse ; |
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81 | dydx[1] = y[4]*pModuleInverse ; |
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82 | dydx[2] = y[5]*pModuleInverse ; |
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83 | |
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84 | dydx[3] = cof1*(cof2*Field[0] - (y[4]*Field[5] - y[5]*Field[4])) ; |
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85 | |
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86 | dydx[4] = cof1*(cof2*Field[1] - (y[5]*Field[3] - y[3]*Field[5])) ; |
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87 | |
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88 | dydx[5] = cof1*(cof2*Field[2] - (y[3]*Field[4] - y[4]*Field[3])) ; |
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89 | |
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90 | dydx[6] = 0.;//not used |
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91 | |
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92 | // Lab Time of flight |
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93 | dydx[7] = inverse_velocity; |
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94 | return ; |
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95 | } |
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