Molecular Hydrogen Density Measurements Of Short-pulse, High-density Fueling From A Molecular Cluster Injector
Authors: D.P. Lundberg, R. Kaita and R. Majeski
Abstract:
A Molecular Cluster Injector (MCI) has been developed to provide
short-pulse, high-density fueling for the Lithium Tokamak Experiment (LTX).
Using an electron beam fluorescence method, the molecular density profiles
produced by the injector are measured with sub-cm spatial resolution. The
system, which is cryogenically cooled to promote the formation of molecular
clusters, demonstrates a significant increase in molecular density relative to room-
temperature supersonic gas injectors. The transient characteristics of short pulses
(3-5ms) are measured with 250μs temporal resolution, and the jet shock structure
is found to evolve significantly on that time scale. Supplemental measurements
with a pressure transducer validate the electron beam measurements. The
measured density profiles are consistent with supersonic flows suitable for
producing substantial populations of molecular clusters. The measured densities
and flow-rates are appropriate for high-density fueling of LTX plasmas. The MCI
will be used to investigate the physics of molecular cluster fueling of LTX plasmas.
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Submitted to: Nuclear Fusion (July 2011)
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Download PPPL-4698 (pdf 266 KB 18 pp)
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