title: Spectral emission measurements of lithium on the lithium tokamak experiment.
abstract: There has been a long-standing collaboration between ORNL and PPPL on edge and boundary layer physics. As part of this collaboration, ORNL has a large role in the instrumentation and interpretation of edge physics in the lithium tokamak experiment (LTX). In particular, a charge exchange recombination spectroscopy (CHERS) diagnostic is being designed and undergoing staged testing on LTX. Here we present results of passively measured lithium emission at 5166.89 A in LTX in anticipation of active spectroscopy measurements, which will be enabled by the installation of a neutral beam in 2013. Preliminary measurements are made in transient LTX plasmas with plasma current, I(p) < 70 kA, ohmic heating power, P(oh) ∼ 0.3 MW and discharge lifetimes of 10-15 ms. Measurements are made with a short focal length spectrometer and optics similar to the CHERS diagnostics on NSTX [R. E. Bell, Rev. Sci. Instrum. 68(2), 1273-1280 (1997)]. These preliminary measurements suggest that even without the neutral beam for active spectroscopy, there is sufficient passive lithium emission to allow for line-of-sight profile measurements of ion temperature, T(i); toroidal velocity and v(t). Results show peak T(i) = 70 eV and peak v(t) = 45 km/s were reached 10 ms into the discharge.
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. tkgray@pppl.gov
authors.forename: T K
authors.initials: TK
authors.lastname: Gray
authors.forename: T M
authors.initials: TM
authors.lastname: Biewer
authors.forename: D P
authors.initials: DP
authors.lastname: Boyle
authors.forename: E M
authors.initials: EM
authors.lastname: Granstedt
authors.forename: R
authors.initials: R
authors.lastname: Kaita
authors.forename: R
authors.initials: R
authors.lastname: Maingi
authors.forename: R P
authors.initials: RP
authors.lastname: Majeski