Turbulence

In order to ensure ITER’s success, a solid theory on the fusion fuel behavior in the outermost plasma region of magnetic confinement devices is needed. This scrape-off layer (SOL) region determines the boundary conditions for the core plasma, controls the plasma refuelling, heat losses and impurity dynamics and regulates the interaction of the plasma with the wall.

Schematic representation of Tokamak SOL plasma defined by poloidal limiter, with long stretched open field line.

As ions and electrons freely flow along the SOL field lines, the energy flux to the vessel can be very large, potentially exceeding the limits of the plasma facing materials. In this region, turbulent phenomena occur on a wide range of spatiotemporal scales, and some approximations typically used to study the plasma core (such as small-amplitude fluctuations) are not valid. Furthermore, the open field line geometry and the presence of X-points complicates our analysis.

SOL drift wave turbulence with characteristic blob ejection in outward mid plane in Tokamak plasma.

 

Active collaborations involve :

– Swiss Plasma Center group in Lausanne for the numerical modelling of the SOL with the GBS code and theoretical development of SOL models for arbitrary collisionality.

– Faculdade Ciências Lisboa on mathematical aspects of two-fluid SOL turbulence