A plasma arc system includes a plasma torch having a torch nozzle with an opening at a distal end for a plasma jet to exit. An electromagnetic shield cap is disposed near the distal end of the torch nozzle with the shield cap having an opening that is coaxial with the opening of the torch nozzle. A plasma cutting power source supplies current to the torch to create the plasma jet. A magnetic field power source provides a current to the electromagnetic shield cap to generate a magnetic field near the plasma jet to focus the plasma jet as the plasma jet exits the torch nozzle. A controller synchronizes operation of the power sources during a transition from a piercing operation to a cutting operation.