A high-current magnetically stabilized plasma column for fast current-reversal and penetration studies

Publisher Website
Google Scholar
Abstract
A magnetically stabilized He-plasma column with a diameter of about 40 mm is operated in the electron density and temperature range of 1021 m−3 and 5 eV, respectively. The temperature is inferred through spectroscopy from the He line-to-line ratio, and the density profile at a given time is obtained on a single shot from interferometry with a large cross-section Mach-Zehnder. At equilibrium a simple balance between ohmic heating and dominant longitudinal conduction losses predicts a core temperature in relatively good agreement with the measurements. At a given time during the long lasting discharge (milliseconds), the 10-kA current can be completely reversed on a time scale (microseconds) much shorter than the classical time for current penetration toward the center of the column. This plasma device is useful for studying basic energy transport and anomalous current-penetration mechanisms involved in hot and relatively dense plasmas.