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A novel experiment to measure ion self-helicity conservation

Author: Setthivoine You
Requested Type: Poster Only
Submitted: 2011-06-10 19:03:48

Co-authors: J. von der Linden, L. Paritzky, S. Jacobs, J. Geier

Contact Info:
University of Washington
3795 East Stevens Way NE
Seattle, WA   98195
USA

Abstract Text:
Two-fluid theory predicts the conservation of ion self-helicity during plasma relaxation [1], but to date no experimental verification has yet been made. We propose to test the prediction with a new experiment currently being built with unique diagnostics for observing plasma jet collisions with compact toroids. A pair of conical theta pinches will merge two compact toroids at the center of a large vacuum chamber and another pair of planar coaxial guns will shoot smaller plasma jets tangentially on to the compact torus to induce net bulk angular rotation. A large vacuum chamber, flexible gas injection arrangements and all power supplies are designed to allow for a range of {S∗;Beta} values and ion flow velocities to explore regimes with two-fluid effects on compact toroid configurations. For each shot, two sequential ion flow maps can be reconstructed from 3D vector tomography of multichannel ion Doppler spectroscopy measurements [2]. Bulk ion line emission from non-hydrogen plasmas will be measured. Together with an insertable 3D array of Bdot probes to measure the magnetic field and helicity, the ion self-helicity can be measured in the entire 3D volume twice in each discharge. A fast ion gauge will measure time-resolved neutral gas profiles to help reduce plasma edge neutral densities and optimize gas injection times. A novel two-fluid plasma lattice Boltzmann numerical model [3] is being developed to support the interpretation of experimental measurements.
[1] L.C. Steinhauer, A. Ishida, Phys. Plasmas, 5, 7, (1998)
[2] S. You, H. Tanabe, Y. Ono, A.L. Balandin, J. Fusion Energy, 29 (2010)
[3] J. von der Linden, S. You, Two-fluid Plasma Lattice Boltzmann model, this meeting.

Characterization: D3

Comments:
Please place next to J. von der Linden poster.

University of Washington

Workshop on Innovation in Fusion Science (ICC2011) and
US-Japan Workshop on Compact Torus Plasma
August 16-19, 2011
Seattle, Washington

ICC 2011