Measurement of Reynolds stress using Langmuir probes in the HSX stellarator

POSTER

Abstract

A compact Langmuir probe configuration has been designed and implemented in the edge of plasmas in the HSX stellarator to measure the Reynolds stress contribution to the momentum balance in multiple directions. Measurements are made of the fluctuating values of the radial and poloidal electric field, simultaneously with mach probe measurements of fluctuating values of the parallel flow. Experiments are performed in plasmas with an external bias applied as well as in the unbiased equilibrium case to study the effect of a large radial electric field on the fluctuations. The effect of quasi-helical symmetry on fluctuation-driven flows is also investigated by comparing measurements in an optimized magnetic configuration (QHS) to those in a configuration which has the optimization intentionally degraded (Mirror).

*Supported under US DOE grant DE-FG02-93ER54222.

Authors

  • R.S. Wilcox

    • HSX Plasma Lab, University of Wisconsin

  • J.A. Alonso

    • CIEMAT, Madrid, Spain

  • D. Carralero

    • CIEMAT, Madrid, Spain

  • D.T. Anderson

    • University of Wisconsin
    • HSX Plasma Lab, University of Wisconsin
    • HSX Plasma Laboratory, University of Wisconsin-Madison
    • HSX Plasma Lab, Univeristy of Wisconsin
    • HSX Plasma Lab, University of Wisconsin, Madison
    • University of Wisconsin-Madison

  • J.N. Talmadge

    • University of Wisconsin
    • HSX Plasma Lab, University of Wisconsin
    • HSX Plasma Laboratory, University of Wisconsin-Madison
    • University of Wisconsin, Madison
    • HSX Plasma Lab, University of Wisconsin, Madison

  • F.S.B. Anderson

    • HSX Plasma Lab, University of Wisconsin
    • HSX Plasma Lab, Univeristy of Wisconsin
    • HSX Plasma Lab, University of Wisconsin, Madison