National Institute for Fusion Science, Japan and Southwest Jiaotong University, China are making collaboration in a joint project NSJP for constructing a new stellarator CFQS in China [1, 2, 3]. The device design concept is based on the quasi-axisymmetric advanced stellarator. As well as good performances of confinement properties of core region, the magnetic configuration of the peripheral region is very important because the diverter performance is crucial for the successful achievement of the future reactor design. For the present stellarator experiments, two leading concepts for the divertor are well known. In LHD, the intrinsic helical divertor has divertor magnetic field lines connecting the ergodic boundary layer of the core confinement region and the divertor plates on the wall [4]. In Wendelstein 7-X, the island divertor provides a sophisticated divertor structure combined with small islands created near the boundary of the core confinement region [5]. For the new stellarator CFQS in China, we are designing a new divertor configuration which provides a sufficiently long connection length of magnetic field lines between the plasma boundary and the wall.
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