Scrape-Off Layer physics in limited plasmas in TCV

The plasma-wall interaction through the SOL is believed to strongly affect future fusion reactors performances, and the elevated heat loads on the solid surfaces are one of the most limiting factors for fusion. We advance the understanding of SOL physics in limited plasmas, the simplest magnetic configuration, combining experiments and numerical simulations. In particular, two topics are addressed. First, the separation of the SOL into two different regions, the “near” and “far” SOL, is investigated. The near SOL extends typically a few mm from the LCFS, features steep radial profiles of parallel heat flux and is responsible for the peak of heat deposition on the tokamak first wall. The far SOL, typically a few cm wide, features flatter heat flux profiles, and accounts for the majority of the heat deposited on the first wall. In a second instance, blob dynamics is investigated. Blobs are high density plasma filaments generated by turbulence, and are an ubiquitous feature of plasmas in open magnetic field line configurations. Blobs are self-propelled and travel outwards to the reactor walls, substantially increasing  cross field transport.