The effect of static magnetic field configuration on the ion production efficiency and operational stability of a microwave plasma source

Summary form only given. In the last five years interest has grown in non-magnetized, large area, low pressure microwave plasma sources. The advantages of eliminating costly, bulky, high power consuming electromagnets or permanent magnets from a plasma system are clear. We should then ask: Is a static B-field ever necessary? Under what conditions do static B-fields increase or decrease plasma source performance? To answer these questions a microwave plasma source is evaluated with three different static B-field configurations: 1) a standard multipolar permanent magnet array with 8 alternating pole faces around the discharge chamber, 2) an axially directed divergent B-field produced by a large permanent magnet near the top of the discharge chamber, and 3) no magnets.