Dust measurements in tokamaks (invited)
2008 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 79, no 10, 10F303- p.Article in journal (Refereed) Published
Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 mu m in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C(2) dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.
Place, publisher, year, edition, pages
2008. Vol. 79, no 10, 10F303- p.
dusty plasmas, electrostatic devices, image sensors, laser beams, Mie scattering, particle size measurement, plasma diagnostics, solid lasers, Tokamak devices
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-38061DOI: 10.1063/1.2969422ISI: 000260573500222ScopusID: 2-s2.0-55449136342OAI: oai:DiVA.org:kth-38061DiVA: diva2:436560
17th Topical Conference on High-Temperature Plasma Diagnostics Location: Albuquerque, NM Date: 20082011-08-242011-08-222011-08-24Bibliographically approved