Pre-plasma remobilization of ferromagnetic dust in FTU and possible interference with tokamak operations. (4th September 2019)

• Record Type: Journal Article
• Authors: De Angeli, M.; Lazzaro, E.; Tolias, P.; Ratynskaia, S.; Vignitchouk, L.; Castaldo, C.; Apicella, M.L.; Gervasini, G.; Giacomi, G.; Giovannozzi, E.; Granucci, G.; Iafrati, M.; Iraji, D.; Maddaluno, G.; Riva, G.; Uccello, A.
• Is Part Of: Nuclear fusion. Volume 59:Number 10(2019:Oct.)
• Publication Date: 2019-09-04
• Subjects: magnetic dust -- dust mobilization -- discharge start-up -- discharge breakdown -- dust in tokamaks; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/1741-4326/ab369f
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: Experimental evidence of the pre-plasma remobilization of ferromagnetic dust in FTU is presented. Thomson scattering data and IR camera observations document the occurrence of intrinsic dust remobilization prior to discharge start-up and allow for a rough calculation of the average mobilized dust density. Exposures of calibrated extrinsic non-magnetic and ferromagnetic dust to sole magnetic field discharges reveal that the magnetic moment force is the main mobilizing force, as confirmed by theoretical estimates. Pre-plasma remobilization probabilities are computed for varying dust sizes. The impact of prematurely remobilized dust on the breakdown and burn-through start-up phases is investigated together with the discharge termination induced once the plasma plateau is established.