Plasma growth processes inside gaps of the castellated limiter of the Tore Supra tokamak

R. Ruffe , C. Martin , C. Pardanaud , G. Giacometti , P. Languille , P. Roubin , B. Pégourié

We performed electron microscopy analysis of carbon tiles dismantled from the toroidal limiter of the Tore Supra tokamak. The tile top surfaces are either eroded, or covered with deposits, depending on ion flux. On the contrary, the tile gap surfaces are covered with deposits whatever the region of the limiter. We analyzed both the topography and the microstructure of gap deposits. Deposits are tip-shaped and deposition is significant only down to ~1 mm, due to the limited penetration of ions. The direction of tips results from the combination of the ion speed along the magnetic lines and the drift associated to the local electric fields. The microstructure of deposits reveals the presence of graphitic species, such as onion-like nanoparticles, and our results therefore show that deposition results from local plasma chemistry similar to what is observed for cold plasmas.

Mots clés: Physical Sciences

Domaines: Physique [physics]

R. Ruffe, C. Martin, C. Pardanaud, G. Giacometti, P. Languille, et al.. Plasma growth processes inside gaps of the castellated limiter of the Tore Supra tokamak. European Physical Journal: Applied Physics, 2011, 56 (2), pp.24027. ⟨10.1051/epjap/2011110171⟩. ⟨hal-00746210⟩