Radiative properties of an electrically-vaporized thin film plasma in an external magnetic field

An external magnetic field of a few kilogauss is used to alter significantly the radiative properties of the plasmas generated by the capacitive discharge vaporization of thin Ag films. The magnetic field is generated by the plasma current in a large inductor surrounding the plasma. The magnetic field is oriented normal to the electric field in the plasma. This generates a drift motion of the plasma normal to the plane established by the electric and magnetic field vectors. The drift motion can direct the plasma toward the plastic substrate on which the Ag film and a powder or solution residue sample were originally located. This increases the plasma-sample interaction. Time integrated, spatially resolved photographic spectra and spatially resolved photoeiectric radiation profiles show that with the magnetic field, the continuum background radiation is confined to a relatively small region near the substrate surface. This results in significantly larger analyte line-t~~k~ound intensity ratios in the region l-2 cm above the substrate surface.