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Question Magnetic field vs. Electromagnetic field 

Forum: Fields: Magnetic and Otherwise
Date: 04 Feb, 2011
From: Daniel Cox <Daniel Cox>

I am trying to simulate an electromagnetic field where all the values are read in from a file. I used the code from the Purging Magnet example to read in my values.

To begin with a just read in the magnetic field components using the the exact code from the previously mentioned example. This seems to work fine.

When I try to expand this to be an electromagnetic field however things go wrong, With a pure magnetic fields my electrons follow a helical path but in the electromagnetic field, with all the electric components set to zero, they behave unusually.

Here is the code I use to create a purely magnetic field

      G4MagneticField* SageField= new SageTabulatedField3D("Sage3D.TABLE", zOffset);
      pFieldMgr=G4TransportationManager::GetTransportationManager()->GetFieldManager();
      G4ChordFinder *pChordFinder = new G4ChordFinder(SageField);
      pFieldMgr->SetChordFinder( pChordFinder );
      pFieldMgr->SetDetectorField(SageField);

Here is the code I use to create my electromagnetic field

      HVFieldManager = G4TransportationManager::GetTransportationManager()->GetFieldManager();
      G4ElectroMagneticField* HVField = new SageHVField("field_total.table", zOffset);
      pEquation = new G4EqMagElectricField(HVField);
      G4int nvar = 12;
      pStepper = new G4ClassicalRK4 (pEquation, nvar);
      pIntgrDriver = new G4MagInt_Driver(0.01*mm,pStepper,pStepper->GetNumberOfVariables() );
      pChordFinder = new G4ChordFinder(pIntgrDriver);
      HVFieldManager->SetChordFinder(pChordFinder);
      HVFieldManager->SetDetectorField(HVField);
      HVFieldManager->SetDeltaOneStep( 0.5 * mm );

I'm still very new to Geant4 and relying heavily on examples but I can't see why the electrons don't behave like they do in a magnetic field when they are in an electromagnetic field with no electric component.

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1 Feedback: Re: Magnetic field vs. Electromagnetic field   (Gumplinger Peter - 10 Feb, 2011)
(_ None: Re: Magnetic field vs. Electromagnetic field   (Daniel Cox - 10 Feb, 2011)
(_ Feedback: Re: Magnetic field vs. Electromagnetic field   (Gumplinger Peter - 10 Feb, 2011)
(_ More: Re: Magnetic field vs. Electromagnetic field   (Daniel Cox - 11 Feb, 2011)
(_ More: Re: Magnetic field vs. Electromagnetic field   (Daniel Cox - 16 Feb, 2011)
(_ None: Re: Magnetic field vs. Electromagnetic field   (Daniel Cox - 11 Apr, 2011)
(_ None: Re: Magnetic field vs. Electromagnetic field   (Daniel Cox - 21 Apr, 2011)
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