(1) The new class CombinedElectroMagneticField.cxx and CombinedElectroMagneticField.h are implemented.
(2) The electric field turn on/off functionality is added in /athena/Simulation/G4Atlas/G4AtlasTools/src/DetectorFieldManagerTool.cxx.
For build, used the following setup:
asetup master,Athena,gcc8,latest
After the build (successfully compiled in master), when the Sim_tf.py is run, there is an error - segmentation violation, which needs to be investigated in detail.