Modeling of dust-particle behavior for different materials in plasmas

Abstract

The behavior of dust particles made of different fusion-related materials ͑Li, Be, B, C, Fe, Mo, or W͒ in tokamak plasmas is simulated using the dust transport code DUSTT ͓A. Pigarov et al., Phys. Plasmas 12, 122508 ͑2005͔͒. The dependencies of the characteristic lifetime of dust particles on plasma parameters are compared for the different dust materials. The dynamics of dust particles in the tokamak edge plasma is studied and the effects of dust material on the acceleration, heating, and evaporation/sublimation of particles are analyzed.

Fast camera imaging of dust in the DIII-D tokamak

“…Another concern is that the observed dust may not consist of pure carbon, while the theoretical ablation rate used to estimate dust size is calculated for carbon. A boron particle at 3000 K, for example, sublimates nearly 10Â faster than a carbon particle at the same temperature [15]. The assumption of carbon composition for the dust modeling is reasonable, however, as the bulk of dust collected from the DIII-D vacuum vessel in previous studies is carbon [16].…”

Mass changes in NSTX surface layers with Li conditioning as measured by quartz microbalances

“…In a fusion device such detachment will lead to the generation of flakes and dust containing high Z material and/or tritium. These can either be transported to the plasma core potentially contaminating it with high Z material [10] or fall into inaccessible areas and complicate efforts to control the tritium and dust inventory [11,12,13]. Lithium coatings on the NSTX QMB crystals are of micron scale and exhibit fluctuations in apparent mass that appear to be due to mechanical instabilities.…”

A Simple Apparatus for the Injection of Lithium Aerosol into the Scrape-Off Layer of Fusion Research Devices

“…As seen in the images, solid Li particles in the SOL are heated and ablated by electron impact. Particles quickly liquefy and develop an incandescent neutral ablation cloud, appearing yellow [17,20]. This process continues until complete droplet evaporation occurs.…”