Analysis of spatially resolved Z-pinch spectra to investigate the nature of 'bright spots'

Journal Article · Fri Feb 15 04:00:00 EST 2013 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4792256· OSTI ID:22113457

Apruzese, J. P.; Giuliani, J. L.; Thornhill, J. W. ^[1]; Coverdale, C. A.; Jones, B.; Ampleford, D. J. ^[2]

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1. Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States)
2. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

Localized, intensely radiating regions are often observed in Z pinches. High resolution images of such areas have been recorded at least as far back as the 1970s. However, there is as yet no widely accepted consensus on the nature of these 'bright spots' or how they are formed. This phenomenon has also been referred to 'hot spots' or 'micropinches.' To shed further light on this issue, we have analyzed axially resolved K-shell spectra from 4 Z pinches driven by the refurbished Z generator ('ZR') at Sandia National Laboratories, and the previous version of the Z machine ('Z'). The atomic numbers of the loads varied from 13 to 29. We find that higher spatial K-shell intensity in the Al pinch correlates with density. The K-shell intensity within a copper shot taken on ZR correlates strongly with increased electron temperature, but another, somewhat less well-diagnosed copper shot from Z shows correlation with density. The bright spots in a Ti pinch correlate with neither density nor temperature, but do correlate with the product of density and diameter (proportional to opacity). This opacity correlation is also observed in the other 3 pinches.

• OSTI ID: 22113457
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 2 Vol. 20; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COPPER
CORRELATIONS
DENSITY
ELECTRON TEMPERATURE
HOT SPOTS
ION TEMPERATURE
K SHELL
LONGITUDINAL PINCH
OPACITY
PLASMA DENSITY
PLASMA HEATING
RESOLUTION
SANDIA NATIONAL LABORATORIES
SPECTRA