Author: Dmitri D Ryutov
Requested Type: Poster
Submitted: 2018-02-27 10:32:36
Livermore, California 94550
This study is concerned with divertor configurations created by poloidal field coils situated behind the blanket and, possibly, outside toroidal field coils. We demonstrate that there exist coil arrangements that allow creation of three nulls lying on the same separatrix, thereby reproducing the cusp divertor described in Ref. 1. However, in our case the polodal field coils are situated far away from the divertor area, and a large stand-off distance makes this divertor more attractive in fusion environment. Another advantage of this configuration is its flexibility: by changing the currents in remote coils, one can produce a great variety of divertor configurations. Among them is an X-Point-Target divertor configuration (Ref. 2), but now created not in the outer leg only, as proposed in Ref. 2, but both in the outer and inner divertor legs. Alternatively, the same coil configuration allows creating the X-Point Target in the outer leg only. A benefit in this case is a very strong flux flaring in the target area. A technique for finding these configurations is briefly described based on Ref. 3. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Security, LLC, Lawrence Livermore National Laboratory, under Contract DE-AC52-07NA27344.
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2.B. LaBombard, E. Marmar, J. Irby et al “ADX: a high field, high power density, advanced divertor and RF tokamak.” Nucl. Fusion, 55, 053020, 2015.
3.D.D. Ryutov, V.A. Soukhanovskii,. “The Snowflake Divertor.” Phys. Plasmas, 22, 110901, 2015.