High energy density Z-pinch plasmas using flow stabilization

Journal Article · Mon Dec 15 00:00:00 EST 2014 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4904781· OSTI ID:22390831

Shumlak, U., E-mail: [e-mail]; Golingo, R. P., E-mail: [e-mail]; Nelson, B. A., E-mail: [e-mail]; Bowers, C. A., E-mail: [e-mail]; Doty, S. A., E-mail: [e-mail]; Forbes, E. G., E-mail: [e-mail]; Hughes, M. C., E-mail: [e-mail]; Kim, B., E-mail: [e-mail]; Knecht, S. D., E-mail: [e-mail]; Lambert, K. K., E-mail: [e-mail]; Lowrie, W., E-mail: [e-mail]; Ross, M. P., E-mail: [e-mail]; Weed, J. R., E-mail: [e-mail] ^[1]

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1. Aerospace and Energetics Research Program, University of Washington, Seattle, Washington, 98195-2250 (United States)

The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and scaling analyses will be presented. In addition to studying fundamental plasma science and high energy density physics, the ZaP and ZaP-HD experiments can be applied to laboratory astrophysics.

• OSTI ID: 22390831
• Journal Information: AIP Conference Proceedings, Vol. 1639, Issue 1; Conference: 9. International Conference on Dense Z Pinches, Napa, CA (United States), 3-7 Aug 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPRESSION
EDUCATIONAL FACILITIES
ELECTRON TEMPERATURE
ENERGY DENSITY
INTERFEROMETRY
ION TEMPERATURE
LIFETIME
LINEAR Z PINCH DEVICES
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
PHOTOGRAPHY
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
SHEAR
THOMSON SCATTERING
VISCOSITY
WAVE FORMS
ZEEMAN EFFECT