One disclosed plasma processing system includes a chamber, a substrate support, a plasma generator, and first and second electric magnet assemblies. The substrate support is disposed in the chamber. A center of a substrate on the substrate support is positioned on a central axis of the chamber. The plasma generator is configured to generate a plasma in the chamber. The first electric magnet assembly includes one or more first annular coils and is disposed on or above the chamber and configured to generate a first magnetic field in the chamber. The second electric magnet assembly includes one or more second annular coils and is configured to generate a second magnetic field in the chamber. The second magnetic field reduces the intensity of the first magnetic field in the center of the substrate on the substrate support.