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Strongly Localized Neutral‐Particle Recycling at the Limiter and its Influence on the Operation of a Tokamak
Author(s) -
Alexander Karl F.,
Hintze Wolfgang
Publication year - 1986
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19864980303
Subject(s) - limiter , tokamak , plasma , physics , atomic physics , limiting , nuclear physics , electrical engineering , mechanical engineering , engineering
Abstract Recycling of neutral particles plays an essential role for stationary confinement of the plasma column in a tokamak. With a simple nonlinear particle balance model we showed that under certain conditions the edge plasma density depends approximately quadratically on the central plasma density, in accord with experimental observation [3, 4]. This model is extended here to the case of a highly localized recycling zone (e.g. the limiter edge), and various limiting conditions to be imposed on the central plasma density are derived. These compare favourably with experimentally observed “critical” situations, such as the sharp drop of the power‐density flux incident on the limiter edge in tokamak T‐10 for central plama densities > 5 · 10 19 m −3 [7]. It is concluded that (i) the response of the plasma core to a spatially localized recycling zone may be an interesting effect that deserves further study, (ii) ordinary limiters can be protected above a certain density threshold by the self‐shielding action of the locally recycling plasma.