Spectroscopic investigations of the magnetic field and electron density evolution in a microsecond POS [pulsed power switches]

Spatially resolved measurements in a planar microsecond POS using spectroscopy of dopants in the plasma are presented. The initial plasma properties such as the electron density and temperature and the plasma composition are determined. The magnetic field evolution determined from Zeeman splitting is mapped in 2D and found to propagate axially in the form of a broad current channel, at an average velocity of 3.3/spl times/10/sup 7/ cm/s. Observations of different spectral line intensities and collisional-radiative modelings are used to show that the mean electron energy rises to at least 50 eV during the conduction phase and the electron energy distribution is shown to be nonMaxwellian. The electron density determined from the temporal behavior of various spectral lines is found to drop after the magnetic field reaches 50% of its peak value.