title: Two-photon LIF on the HIT-SI3 experiment: Absolute density and temperature measurements of deuterium neutrals.
abstract: Two-photon laser-induced fluorescence measurements were performed on the helicity injected torus (HIT-SI3) device to determine the density and temperature of the background neutral deuterium population. Measurements were taken in 2 ms long pulsed plasmas after the inductive helicity injectors were turned off. Attempts to measure neutrals during the main phase of the plasma were unsuccessful, likely due to the density of neutrals being below the detection threshold of the diagnostic. An unexpectedly low density of atomic deuterium was measured in the afterglow; roughly 100 times lower than the theoretical prediction of 1017m-3. The neutral temperatures measured were on the order of 1 eV. Temporally and spatially resolved neutral density and temperature data are presented.
authors.affiliation: Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26056, USA.
authors.forename: Drew
authors.initials: D
authors.lastname: Elliott
authors.affiliation: Department of Aerospace Engineering, University of Washington, Seattle, Washington 98105, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Sutherland
authors.affiliation: Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26056, USA.
authors.forename: Umair
authors.initials: U
authors.lastname: Siddiqui
authors.affiliation: Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26056, USA.
authors.forename: Earl
authors.initials: E
authors.lastname: Scime
authors.affiliation: Department of Aerospace Engineering, University of Washington, Seattle, Washington 98105, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Everson
authors.affiliation: Department of Aerospace Engineering, University of Washington, Seattle, Washington 98105, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Morgan
authors.affiliation: Department of Aerospace Engineering, University of Washington, Seattle, Washington 98105, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Hossack
authors.affiliation: Department of Aerospace Engineering, University of Washington, Seattle, Washington 98105, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Nelson
authors.affiliation: Department of Aerospace Engineering, University of Washington, Seattle, Washington 98105, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Jarboe