The effect of magnetic field configuration on plasma beam profiles in curved magnetic filters

Curved magnetic filters are commonly used with cathodic vacuum arcs to remo ve macroparticles from the plasma stream, making it suitable for the prepar ation of smooth, dense, and defect free films. Although a variety of filter s have been investigated experimentally, the influence of the magnetic fiel d configuration on the shape and position of the plasma beam at the filter exit has not been recognized. In this work the magnetic field configuration s for a wide range of filter designs have been calculated and compared with measured beam profiles. The results show that the field configurations can be used to predict the dimensions of the plasma beam and in-plane off-axis shifts at the filter exit, as well as identifying regions of high loss. Ma gnetic field configuration calculations are shown to be a valuable design a nd optimization tool for curved magnetic field filters of various designs. (C) 1999 American Institute of Physics. [S0021-8979(99)08709-5].