Author/Authors :
Petrie، نويسنده , , T.W. and Brooks، نويسنده , , N.H. and Fenstermacher، نويسنده , , M.E. and Groth، نويسنده , , M. and Hyatt، نويسنده , , A.W. and Lasnier، نويسنده , , C.J. and Leonard، نويسنده , , A.W. and Porter، نويسنده , , G.D. and Schaffer، نويسنده , , M.J. and Wade، نويسنده , , M.R. and Watkins، نويسنده , , J.G. and West، نويسنده , , W.P.، نويسنده ,
Abstract :
Recent DIII-D experiments show that both magnetic balance and particle drifts are important to understanding how argon impurities accumulate in balanced and unbalanced double-null plasmas during ‘puff and pump’ radiating divertor operation. Unbalanced double-null shapes, which are biased in the direction opposite to the ion B × ∇ B drift direction, have produced the best result to-date in terms of coupling a radiating divertor approach with an H-mode plasma. The proximity to balanced double-null that can be used for puff-and-pump may depend on the width of the heat flux profile in the scrape-off layer. A comparison of plasma behavior in the open lower divertor to that of the more closed upper divertor determined that plasma density control was far more sensitive to the ion B × ∇ B drift direction than to the relative closure of the divertor.
