The ZaP Flow Z-Pinch: Plasma Flow Shear and Stability

Journal Article · Sat Jan 15 04:00:00 EST 2005 · Fusion Science and Technology

OSTI ID:20849803

Hartog, D.J. den; Golingo, R P; Jackson, S L; Nelson, B A; Shumlak, U ^[1]

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1. University of Washington (United States)

The ZaP Flow Z-pinch plasma device at the University of Washington produces a small diameter (20-30 mm) dense Z-pinch plasma with typical electron density 10{sup 22}-10{sup 23} m{sup -3} and ion plus electron temperature 100-200 eV. The plasma is stable, with relatively low magnetic mode activity, for tens of microseconds. This is orders of magnitude longer than predicted by a simple ideal magnetohydrodynamic calculation. The probable stabilizing mechanism is radial shear in the axial plasma flow. The axially flowing Z-pinch is generated with a coaxial accelerator coupled to a pinch assembly chamber. After the pinch assembles a quiescent period occurs, during which the mode activity is significantly reduced. Multichord Doppler shift measurements of impurity lines show a large, sheared flow during the quiescent period and low, uniform flow profiles during periods of high mode activity. The plasma has a sheared axial flow that exceeds the theoretical threshold for stability during the quiescent period and is lower than the threshold during periods of high mode activity. The Z-pinch plasmas are globally stable for 700-2000 times the theoretically predicted kink growth time of a static Z-pinch. The end of the quiescent period corresponds to a decrease in acceleration of plasma and possibly suggests a means to extend the experiment to quasi-steady-state operation.

• OSTI ID: 20849803
• Journal Information: Fusion Science and Technology, Journal Name: Fusion Science and Technology Journal Issue: 1T Vol. 47; ISSN 1536-1055
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
DOPPLER EFFECT
ELECTRON DENSITY
ELECTRON TEMPERATURE
EV RANGE
IONS
KINK INSTABILITY
LINEAR Z PINCH DEVICES
LONGITUDINAL PINCH
PLASMA
PLASMA ACCELERATION
PLASMA IMPURITIES
SHEAR
STABILITY
STEADY-STATE CONDITIONS