Dust Studies in DIII-D Tokamak

Journal Article · Sun Sep 07 00:00:00 EDT 2008 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2997272· OSTI ID:21251315

Rudakov, D L; Yu, J H; Boedo, J A; Hollmann, E M; Krasheninnikov, S I; Moyer, R A; Pigarov, A Yu; Smirnov, R ^[1]; West, W P; Bray, B D; Brooks, N H; Hyatt, A W; Wong, C P. C. ^[2]; Groth, M; Fenstermacher, M E; Lasnier, C J ^[3]; Solomon, W M ^[4]

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1. University of California, San Diego, La Jolla, California 92093-0417 (United States)
2. General Atomics, San Diego, California 92186-5608 (United States)
3. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
4. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

Studies of submicron dust using Mie scattering from Nd:YAG lasers and video data of micron to sub-millimeter sized dust on DIII-D tokamak have provided the first data of dust sources and transport during tokamak discharges. During normal operation on DIII-D dust observation rates are low, a few events per discharge or less. The net carbon content of the dust corresponds to a carbon atom density a few orders of magnitude below the core impurity density. Statistical analysis of Mie data collected over months of operation reveal correlation of increased dust rate with increased heating power and impulsive wall loading due to edge localized modes (ELMs) and disruptions. Generation of significant amounts of dust by disruptions is confirmed by the camera data. However, dust production by disruptions alone is insufficient to account for estimated in-vessel dust inventory in DIII-D. After an extended entry vent, thousands of dust particles are observed by cameras in the first 2-3 plasma discharges. Individual particles moving at velocities up to {approx}300 m/s, breakup of larger particles into pieces, and collisions of particles with walls are observed. After {approx}70 discharges, dust levels are reduced to a few events per discharge. In order to calibrate diagnostics and benchmark modeling, milligram amounts of micron-sized carbon dust have been injected into DIII-D discharges, leading to the core carbon density increase by a factor of 2-3. Following injection, dust trajectories in the divertor are mostly in the toroidal direction, consistent with the ion drag force. Dust from the injection is observed in the outboard midplane by a fast framing camera. The observed trajectories and velocities of the dust particles are in qualitative agreement with modeling by the 3D DustT code.

• OSTI ID: 21251315
• Journal Information: AIP Conference Proceedings, Vol. 1041, Issue 1; Conference: 5. international conference on the physics of dusty plasmas, Ponta Degada, Azores (Portugal), 18-23 May 2008; Other Information: DOI: 10.1063/1.2997272; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CAMERAS
CARBON
COMPUTERIZED SIMULATION
CORRELATIONS
D CODES
DIVERTORS
DOUBLET-3 DEVICE
DUSTS
EDGE LOCALIZED MODES
PARTICLES
PLASMA
PLASMA CONFINEMENT
PLASMA DIAGNOSTICS
PLASMA DISRUPTION
PLASMA IMPURITIES
PLASMA SIMULATION
RF SYSTEMS
SPUTTERING
STEADY-STATE CONDITIONS