Among dust particles of various origins collected in the MAST vessel, large quantities of carbon nanoparticles are observed. They are produced in the coldest plasma regions from the nucleation of carbonaceous species originating from physical and chemical erosion of the graphitic plasma facing components. On the other hand, laboratory plasmas studies show that in an environment of reactive carbonaceous species, complex chemical pathways lead to various molecular precursors which depend strongly on plasma conditions. The latter vary very often in a tokamak. Nevertheless, the final nanoparticles produced in laboratory plasmas and in MAST present similarities, giving indications on common growth processes in the plasma.
