Hyperdiffusion of dust particles in a turbulent fusion plasma


Friday, 14 June, 2024 - 15:00 to 16:00

Speaker : Federico Nespoli, Princeton Plasma Physics Laboratory

Time : 15:00 - 16.00 CEST (Rome/Paris)

Hosted at: SISSA, International School of Advanced Studies, Trieste, Italy

YouTube : Processing

Organizers : Pavan Pranjivan Mehta* (pavan.mehta@sissa.it) and Arran Fernandez** (arran.fernandez@emu.edu.tr)

* SISSA, International School of Advanced Studies, Italy

** Eastern Mediterranean University, Northern Cyprus

Keywords: Plasma turbulence, dust, diffusive processes

Abstract: Tokamaks and stellarators are a promising candidate for future nuclear fusion reactors, where a hot, turbulent plasma is confined by a toroidal magnetic field. Due to the interaction of the plasma with the solid walls of the reactor, dust is produced and enters the plasma, polluting it. Furthermore, in recent experiments dust is introduced deliberately into the fusion plasma, for a range of different applications including turbulence control and wall conditioning. The understanding of the dust dynamics in a turbulent fusion plasma is therefore an active topic of research.

In this talk, we investigate the effect of plasma turbulence on the dust dynamics, using the ad hoc developed Dust Injector Simulator code [1] in combination with a turbulent plasma background computed by the TOKAMK3X code [2] in tokamak geometry. The plasma turbulence is observed to scatter the dust particles, exhibiting a hyperdiffusive regime in all cases. The amplitude of the turbulent spread of the trajectories is characterized in terms of the adimensional parameters defining the system, namely the Stokes number and the Kubo number. The results are interpreted with a simple analytical model.

Biography: Federico Nespoli is a staff research physicist at Princeton Plasma Physics Laboratory. He is working on both experiments and simulations on the effect of impurities on the plasma edge in stellarators and tokamaks. Federico earned his bachelor and master in Physics at Universita' degli Studi di Milano in Italy, and his PhD from Ecole Federale Polytechnique Lausanne in Switzerland. After that he worked as a postdoctoral researcher at Aix-Marseille University in France and finally moved to Princeton Plasma Physics Laboratory, USA.


[1] F. Nespoli et al., ”Hyperdiffusion of dust particles in a turbulent tokamak plasma”, Physics of Plasmas 28, 073704 (2021)

[2] P. Tamain et al., “The TOKAM3X code for edge turbulence fluid simulations of tokamak plasmas in versatile magnetic geometries,” Journal of Computational Physics 321, 606–623 (2016).