Magnetic-field modulation of a two-electrode direct-current plasma

Abstract

The magnetic field produced by a pair of electromagnets is used to alter the shape and location of the current channel in a two-electrode direct-current plasma (DCP) designed for solution aerosol analysis. The magnetic field B is oriented normal to the electric field E in the plasma. This results in an E-cross-B (E x B) drift motion of plasma electrons. Experiments are described using both cw and oscillating magnetic fields. With continuous wave (cw) fields of 10-20 G, the current channel can be shaped to improve sample aerosol penetration. Oscillating fields in the frequency range 25-500 Hz cause the current channel to oscillate. At the higher frequencies, the current channel loses its discrete character and the plasma becomes more diffuse.