arXiv subjects

S. Bardin

Publications and source records attributed to S. Bardin.

3 recordsLinked to original sources

arXiv2015

Dust remobilization in fusion plasmas under steady state conditions

The first combined experimental and theoretical studies of dust remobilization by plasma forces are reported. The main theoretical aspects of remobilization in fusion devices under steady state conditions are analyzed. In particular, the dominant role of adhesive forces is highlighted and generic remobilization conditions - direct lift-up, sliding, rolling - are formulated. A novel experimental technique is proposed, based on controlled adhesion of dust grains on tungsten samples combined with detailed mapping of the dust deposition profile prior and post plasma exposure. Proof-of-principle experiments in the TEXTOR tokamak and the EXTRAP-T2R reversed-field pinch are presented. The versatile environment of the linear device Pilot-PSI allowed for experiments with different magnetic field topologies and varying plasma conditions that were complemented with camera observations.

physics.plasm-ph↗

arXiv2010

Automatic detection and tracking of dust particles in a RF plasma sheath

A method enabling automatic detection and tracking of large amounts of individual dust particles in plasmas is presented. Individual trajectories can be found with a good spatiotemporal resolution, even without applying any external light source to facilitate detection. Main advantages of this method is a high portability and the possibility of making statistical analyses of the trajectories of a large amount of non uniformly size distributed particles, under challenging illumination conditions and with low time and computational resources. In order to evaluate the efficiency of different detection and tracking strategies statistically, an experimental benchmark is proposed, and completed by numerical simulations.

physics.data-an↗

arXiv2010

Investigating transport of dust particles in plasmas

An algorithm has been developped, which makes it possible to automatically extract trajectories of a large number of particles from fast imaging data, allowing a statistical analysis of particles trajectories under various plasma conditions, a better understanding of their influence on plasma properties, and a better characterization of the plasma itself. In this contribution, we focus on results obtained in a radiofrequency parallel plate reactor, where a large amount of micron-sized carbon dust is produced in situ. The use of the rescaled range analysis (R/S analysis) applied to dust particles displacements allows decomposing dust dynamic on different time scales. It is shown that dust displacement is dominated by collisions on short time scales whereas long term behaviour is strongly influenced by large scale plasma fluctuations.

physics.plasm-ph↗