Gabriele Cosmo
98 lines
3.7 KiB
C++
98 lines
3.7 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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// $Id: G4EqMagElectricField.cc 69699 2013-05-13 08:50:30Z gcosmo $
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//
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//
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// This is the standard right-hand side for equation of motion.
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//
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// The only case another is required is when using a moving reference
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// frame ... or extending the class to include additional Forces,
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// eg an electric field
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//
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// 10.11.98 V.Grichine
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//
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// -------------------------------------------------------------------
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#include "G4EqMagElectricField.hh"
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#include "globals.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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void
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G4EqMagElectricField::SetChargeMomentumMass(G4ChargeState particleCharge,
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G4double,
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G4double particleMass)
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{
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G4double pcharge = particleCharge.GetCharge();
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fElectroMagCof = eplus*pcharge*c_light ;
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fMassCof = particleMass*particleMass ;
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}
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void
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G4EqMagElectricField::EvaluateRhsGivenB(const G4double y[],
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const G4double Field[],
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G4double dydx[] ) const
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{
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// Components of y:
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// 0-2 dr/ds,
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// 3-5 dp/ds - momentum derivatives
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G4double pSquared = y[3]*y[3] + y[4]*y[4] + y[5]*y[5] ;
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G4double Energy = std::sqrt( pSquared + fMassCof );
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G4double cof2 = Energy/c_light ;
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G4double pModuleInverse = 1.0/std::sqrt(pSquared) ;
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// G4double inverse_velocity = Energy * c_light * pModuleInverse;
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G4double inverse_velocity = Energy * pModuleInverse / c_light;
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G4double cof1 = fElectroMagCof*pModuleInverse ;
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// G4double vDotE = y[3]*Field[3] + y[4]*Field[4] + y[5]*Field[5] ;
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dydx[0] = y[3]*pModuleInverse ;
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dydx[1] = y[4]*pModuleInverse ;
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dydx[2] = y[5]*pModuleInverse ;
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dydx[3] = cof1*(cof2*Field[3] + (y[4]*Field[2] - y[5]*Field[1])) ;
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dydx[4] = cof1*(cof2*Field[4] + (y[5]*Field[0] - y[3]*Field[2])) ;
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dydx[5] = cof1*(cof2*Field[5] + (y[3]*Field[1] - y[4]*Field[0])) ;
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dydx[6] = 0.;//not used
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// Lab Time of flight
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dydx[7] = inverse_velocity;
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return ;
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}
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