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Author Siddiqui, M. Umair ♦ Thompson, Derek S. ♦ McIlvain, Julianne M. ♦ Short, Zachary D. ♦ Scime, Earl E.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PLASMA PHYSICS AND FUSION TECHNOLOGY ♦ COLLISIONS ♦ DENSITY ♦ DIFFUSION ♦ FLUCTUATIONS ♦ FLUORESCENCE ♦ IONS ♦ KHZ RANGE ♦ LASER RADIATION ♦ MAGNETIC FIELDS ♦ PLASMA ♦ PLASMA POTENTIAL ♦ SPECTRA
Abstract Direct laser induced fluorescence measurements are shown of cross-field ion flows normal to an absorbing boundary that is aligned parallel to the axial magnetic field in a helicon plasma. We show Langmuir and emissive probe measurements of local density and plasma potential in the same region, as well as floating probe spectra near the boundary. With these measurements, we investigate the influence of ion-neutral collisionality on radial ion transport by varying the ratio of the ion gyro-radius, ρ{sub i}, to the ion-neutral collision length, λ, over the range 0.34 ≤ ρ{sub i}λ{sup −1} ≤ 1.60. Classical drift-diffusion transport along density and potential gradients is sufficient to describe flow profiles for most cases. For two parameter regimes (ρ{sub i}λ{sup −1} = 0.65 and 0.44), low-frequency electrostatic fluctuations (f < 10 kHz) and enhanced cross-field bulk ion flow to the boundary are observed.
ISSN 1070664X
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-12-15
Publisher Place United States
Journal Physics of Plasmas
Volume Number 22
Issue Number 12


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