Time-Resolved Thomson Scattering on Gas-Puff Z-Pinch Plasmas at Pinch Time

Journal Article · Tue Aug 21 00:00:00 EDT 2018 · IEEE Transactions on Plasma Science

DOI:https://doi.org/10.1109/TPS.2018.2860927· OSTI ID:1466251

Rocco, S. V. R. ^[1]; Banasek, J. T. ^[1]; Potter, W. M. ^[1]; Kusse, B. R. ^[1]; Hammer, D. A. ^[1]

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1. Cornell Univ., Ithaca, NY (United States)

The conditions and dynamics of neon gas puff Z-pinch plasmas at pinch time are studied on a pulsed power generator with a current rise time of approximately 200-ns and 0.9-mA peak current. Radial tailoring of the gas puff massdensity profile using a triple-nozzle coaxial valve (two annular gas liners and a central jet) allows production of both more stable and less stable (with regard to the magneto-Rayleigh– Taylor instability) Z-pinch implosions. A 526.5-nm, 10-J Thomson scattering diagnostic laser enables probing of the flow dynamics and plasma conditions of these implosions with both spatial and temporal resolutions. The 2.2-ns laser pulse scatters from the plasma electrons and is carried by one optical fiber to a visible light streak camera, and by a bundle of optical fibers to a time-gated camera, both after spectral dispersion by 750-mm spectrometers. The streak camera, with a 10-ns full streak time, provides subnanosecond resolution of the evolution of the pinch plasma parameters through stagnation. The timegated camera provides spatially resolved spectra (across a field of view of 6.1 mm) at the same time as the streak. Scattering spectra suggest that temperatures are high at stagnation, with the ion temperature as much as three times higher than the electron temperature. Furthermore, we consider the possibility of nonthermal explanations for the broad scattering spectra and high effective ion temperature, including collisionality, implosion velocity distributions (velocity gradients), and small-scale hydrodynamic motion.

• Research Organization: Cornell Univ., Ithaca, NY (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: NA0003764
• OSTI ID: 1466251
• Journal Information: IEEE Transactions on Plasma Science, Vol. 46, Issue 11; ISSN 0093-3813
• Publisher: IEEE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
plasma diagnostics
plasma measurements
plasma properties