Exploration of Stellarator Configuration Space with Global Search Methods

Mynick, H.E. ; Pomphrey, N. ; Ethier, S.

Princeton University. Plasma Physics Laboratory.

关键词: 70 Plasma Physics And Fusion Technology;    Axial Symmetry;    Stellarators;    Algorithms;    Design;   

DOI  :  10.2172/788261
RP-ID  :  PPPL-3610
RP-ID  :  AC02-76CH03073
RP-ID  :  788261

美国|英语

来源: UNT Digital Library

【 摘 要 】

An exploration of stellarator configuration space z for quasi-axisymmetric stellarator (QAS) designs is discussed, using methods which provide a more global view of that space. To this end, we have implemented a ''differential evolution'' (DE) search algorithm in an existing stellarator optimizer, which is much less prone to become trapped in local, suboptimal minima of the cost function chi than the local search methods used previously. This search algorithm is complemented by mapping studies of chi over z aimed at gaining insight into the results of the automated searches. We find that a wide range of the attractive QAS configurations previously found fall into a small number of classes, with each class corresponding to a basin of chi(z). We develop maps on which these earlier stellarators can be placed, the relations among them seen, and understanding gained into the physics differences between them. It is also found that, while still large, the region of z space containing practically realizable QAS configurations is much smaller than earlier supposed.