Return To: Session ICP - Innovative Concepts
Prev Page: (ICP/11) Physics Issues of Compact Drift Optimized Stellarators
Next Page: (ICP/13) Reactor Advantages of the Belt Pinch and

(ICP/12) Evidence of Flow Stabilization in the ZaP Z Pinch Experiment

U. Shumlak¹⁾, E. Crawford¹⁾, R. P. Golingo¹⁾, B. A. Nelson¹⁾, A. Zyrmpas¹⁾, D. J. Den Hartog²⁾, D. J. Holly^2)
 
1) Aerospace & Energetics Research Program, Univ. Washington, Seattle, Washington, USA
²⁾ Sterling Scientific, Inc., Madison, Wisconsin, USA

Abstract.  The stabilizing effect of an axial flow on the m = 1 kink instability in Z pinches has been studied numerically with a linearized ideal MHD model to reveal that a sheared axial flow stabilizes the kink mode when the shear exceeds a threshold. The sheared flow stabilizing effect is investigated with the flow-through Z pinch experiment, ZaP. An azimuthal array of surface mounted magnetic probes located at the midplane of the 50 cm long pinch plasma measures the fluctuation levels of the azimuthal modes m = 1, 2, and 3. After pinch formation a quiescent period is found where the mode activity is reduced to a few percent of the average field. Optical images from a fast framing camera and a HeNe interferometer also indicate a stable pinch plasma during this time. Doppler shift measurements of a C-III line correspond to an axial flow velocity of 9.6×10⁴m/s internal to the pinch. During the time when the axial plasma flow is high, the plasma experiences a quiescent period which lasts approximately 800 exponential growth times predicted by linear theory for a static plasma.

Read the full paper in PDF format.