The highly luminous Ag vapor plasmas produced by the electrical vaporization of Ag thin films with 960-J, 8-kV, 1200-juH discharges are used as atomization cells and excitation sources for the direct determination of V, Mn, Cr, Ni, Sr, Cd, Zn, and Pb in solid powder samples. High circuit Inductance reduces particle size effects and 1.0-mg samples with particles in the 20-30 pm size range can be analyzed with aqueous solution of small particle powder standards if

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The effect of a pulsed magnetic field on spatially resolved emission from a laser plasma at atmospheric pressure was investigated. The pulsed magnetic field, produced by capacitive electrical discharge through a specially designed solenoid, was oriented normal to the laser axis. Temporally integrated emission enhancements due to the magnetic field were found to be most significant when the plasma was formed about 1 mm below the magnetic field axis. The degree of confinement of the plasma increased with magnetic field strength—these studies utilized the maximum magnetic field attainable with this system that did not jeopardize the structural integrity of the solenoid (∼85 kG). Laterally resolved emission characteristics (observed both along and normal to the magnetic field axis) demonstrated significant radial compression and axial expansion of the laser plasma. These effects are explainable by JxB or fluid magnetic pressure interactions. Further deconvolution of dynamic magnetic field effects on plasma atomization/excitation/ionization characteristics require spatially and temporally resolved emission and absorption studies.

Temporally resolved emission and absorbance measurements were made in order to investigate the dynamic effects of a high-intensity pulsed magnetic field on a laser plasma. Temporally resolved emission studies were spatially resolved so that the effects of the magnetic field on plasma propagation both along and normal to the magnetic field could be probed. The mechanism of interaction of the field was investigated by observing plasma emission in spatial zones most likely to be influenced by an induced secondary current in the plasma. Spatial and temporal discrimination of emission enhancements indicated that radial compression was due to static magnetic field interactions with the laser plasma and that mild Joule-heating from the small induced current was most likely responsible for emission enhancements later in time. Spatially integrated absorbance measurements in the decaying plasma showed a decrease in absorbance as a result of the magnetic confinement; this is attributed to an increased rate of condensation of the atoms in the vapor cloud produced by the pinched plasma. More efficient coupling of energy from the magnetic field to the plasma would require low-pressure operation in a controlled atmosphere and/or a pulsed magnetic field having a greater d B/d t.

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