Progress in Turbulence Modeling JET SOL and Edge Phenomena

Fluid turbulence modeling of the Scrape-Off Layer (SOL) has been an area of promising progress. Here we report on results obtained using codes that relax the usual scale separation paradigm in the SOL and treat fluctuations and time averaged background profiles simultaneous and without separating them. Initial modeling is based on an interchange model of the SOL assuming that parallel effects appear in form of loss terms, estimated from assuming sheath limited situations or free expansion with ion sound speed along magnetic field lines depending on the connection length. Excellent progress has been achieved with the ESEL code simulating the SOL of smaller devices. The higher temperature SOL of JET has still been modeled with good success. Compared to the SOL of smaller devices the SOL of JET seems to exhibit more 3D effects which are not included in the 2D nature of the original code, which presumes the absence of drift waves in the edge, and - more importantly - uses plasma streaming off with ion sound speed in the parallel direction for the SOL. We have used several approaches to include these 3D effects.
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EFDC100820 1011.06 Kb