Measurement of the plasma potential in a magnetron discharge and inference of the electric field

Using an emissive probe the structure of the plasma potential V/sub p/ in the bulk plasma of a DC magnetron discharge has been determined for a three different magnetic field configurations. The results reveal a large axial variation in the space potential in the confined plasma, with /spl Delta/V/sub p/ /spl sim/ 25V over a distance of 5 cm, from plasma to target. Using the potential distribution, we calculated the corresponding electric field.