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Title: The universal instability in general geometry

The “universal” instability has recently been revived by Landreman et al. [Phys. Rev. Lett. 114, 095003 (2015)], who showed that it indeed exists in plasma geometries with straight (but sheared) magnetic field lines. Here, it is demonstrated analytically that this instability can be presented in more general sheared and toroidal geometries. In a torus, the universal instability is shown to be closely related to the trapped-electron mode, although the trapped-electron drive is usually dominant. However, this drive can be weakened or eliminated, as in the case in stellarators with the maximum-J property, leaving the parallel Landau resonance to drive a residual mode, which is identified as the universal instability.
Authors:
;  [1]
  1. Max-Planck-Institut für Plasmaphysik, Wendelsteinstr. 1, 17491 Greifswald (Germany)
Publication Date:
OSTI Identifier:
22490119
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 9; Other Information: (c) 2015 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; GEOMETRY; INSTABILITY; LANDAU FLUCTUATIONS; MAGNETIC FIELDS; PLASMA; SHEAR; STELLARATORS; TOROIDAL CONFIGURATION; TRAPPED ELECTRONS; WHO