Author/Authors :
Allen، نويسنده , , S.L. and Boedo، نويسنده , , J.A. and Bozek، نويسنده , , A.S. and Brooks، نويسنده , , N.H. and Carlstrom، نويسنده , , T.N. and Casper، نويسنده , , T.A. and Colchin، نويسنده , , R.J. and Evans، نويسنده , , T.E. and Fenstermacher، نويسنده , , M.E. and Friend، نويسنده , , M.E. and Isler، نويسنده , , R.C. and Jayakumar، نويسنده , , R. and Lasnier، نويسنده , , C.J. and Leonard، نويسنده , , A.W. and Mahdavi، نويسنده ,
Abstract :
We present the results from DIII-D experiments and modeling focused on the divertor issues of an `Advanced Tokamakʹ (AT). Operation at high plasma pressure β with good energy confinement H requires core and divertor plasma shaping and current profile J(r) control with ECH current drive. Transport modeling indicates that the available DIII-D ECH power determines a density and temperature regime for sustained DIII-D AT experiments. We demonstrate that a high-δ, unbalanced double null divertor with cryopumping (D-2000) is a flexible AT divertor. Impurity levels in AT experiments have been reduced by careful alignment of the divertor tiles; this, in turn has changed the time evolution of the core J(r) profiles. New physics has been observed near the X-point and private flux regions, including flow reversal and recombination, that is important in understanding and controlling the flows and thereby the radiation in the divertor region, which reduces the divertor heat flux.
