The invention provides an arc 
coating apparatus having a steering 
magnetic field source comprising steering conductors disposed along the short sides of a rectangular target behind the target, and a magnetic focusing 
system disposed along the long sides of the target in front of the target which confines the flow of 
plasma between magnetic fields generated on opposite long sides of the target. The 
plasma focusing 
system can be used to deflect the 
plasma flow off of the working axis of the 
cathode. Each steering conductor can be controlled independently. In a further embodiment, electrically independent steering conductors are disposed along opposite long sides of the 
cathode plate, and by selectively varying a current through one conductor, the path of the arc spot shifts to widen an 
erosion corridor. The invention also provides a plurality of internal anodes, and optionally a surrounding 
anode for deflecting the 
plasma flow and preserving a high 
ionization level of the plasma. The invention also provides a shield at 
floating potential, restricting the 
cathode spot from migrating into selected regions of the target 
evaporation surface outside of the desired 
erosion zone. The shield may be positioned immediately above the region of the 
target surface in the vicinity of the 
anode, protecting the 
anode from deposition of cathodic evaporate and providing better distribution of cathodic evaporate over the substrates to be coated. The invention further provides correcting magnets adjacent to the short sides of the target, to move the arc spot between the long sides.