Open AccessManipulation of E×B drifts in a slot divertor with advanced shaping to optimize detachment
Author(s) -
Haiying Du,
H.Y. Guo,
P.C. Stangeby,
X. Bonnin,
Gengbin Zheng,
Xuru Duan,
M. Xu
Publication year - 2020
Publication title -
nuclear fusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.774
H-Index - 120
eISSN - 1741-4326
pISSN - 0029-5515
DOI - 10.1088/1741-4326/abb53f
Subject(s) - divertor , plasma , toroid , atomic physics , flux (metallurgy) , ion , fusion power , particle (ecology) , materials science , physics , mechanics , nuclear engineering , tokamak , nuclear physics , oceanography , quantum mechanics , engineering , metallurgy , geology
SOLPS-ITER edge code analysis including drifts shows that optimization of divertor target shaping in a small angle slot (SAS) can strongly influence E × B drift particle fluxes, potentially improving divertor detachment for both toroidal field directions. This is enabled by directing recycling neutrals toward the separatrix from both the common flux region (CFR) and the private flux region (PFR) walls of the slot with a V-shape target in the slot (SAS-V), leading to two separate reinforcing effects, each individually involving positive feed-back: (a) increase of neutral recycling at the PFR wall of the slot due to—and causing—strong radial E × B ion flux from the CFR to the PFR; (b) decrease of E × B loss of ions out of the outer divertor into the inner divertor via the PFR due to reduction of the radial gradient of electron temperature at the outer target caused by the increased particle retention in the outer divertor. This circumvents the general problem for divertor operation with ion B ×∇B toward the X-point: E × B loss of particles from the outer divertor CFR plasma tends to keep it hot and attached. This work identifies a strong interaction between divertor geometry and drifts, a potentially important effect for optimizing advanced divertors for power exhaust in fusion reactors.