Plasma Equilibrium Reconstructions In The Lithium Tokamak Experiment
Authors: Laura Berzak Hopkins, J. Menard, R. Majeski, D.P. Lundberg, E. Granstedt, C. Jacobsen, R. Kaita, T. Kozub and L. Zakharov
Abstract: The Lithium Tokamak Experiment (LTX) (R0 = 0.4 m, a = 0.26 m is designed to explore the lowrecycling,
lithium wall operating regime for magnetically confined plasmas. A set of shell quadrants
internal to the vacuum vessel and conformal to the plasma last closed flux surface is designed to be coated
with lithium to produce the lithium plasma-facing surface. The shell quadrants are highly conductive in
order to maintain an even thermal distribution, but this conductivity also permits eddy currents to flow
that can be larger in magnitude than the plasma current. Due to this effect, plasma start-up is greatly
complicated as is the development of an applicable equilibrium solver code. A suitable code, LTX
LRDFIT, has been developed and benchmarked and has now been used to compare plasma flux surface
reconstructions for discharges before and after initial lithium wall conditioning. Dramatic improvements
in plasma performance and shaping have been noted with the introduction of lithium.
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Submitted to: Nuclear Fusion (February 2012)
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Download PPPL-4734 (pdf 6.25 MB 11 pp)
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