Comparison of Microinstability Properties for Stellarator Magnetic Geometries

Rewoldt, G. ; Ku, L.-P. ; Tang, W.M.

Princeton University. Plasma Physics Laboratory.

关键词: Magnetic Fields;    Symmetry;    70 Plasma Physics And Fusion Technology;    Geometry;    Stellarators;   

DOI  :  10.2172/840916
RP-ID  :  PPPL-4082
RP-ID  :  AC02-76CH03073
RP-ID  :  840916

美国|英语

来源: UNT Digital Library

【 摘 要 】

The microinstability properties of seven distinct magnetic geometries corresponding to different operating and planned stellarators with differing symmetry properties are compared. Specifically, the kinetic stability properties (linear growth rates and real frequencies) of toroidal microinstabilities (driven by ion temperature gradients and trapped-electron dynamics) are compared, as parameters are varied. The familiar ballooning representation is used to enable efficient treatment of the spatial variations along the equilibrium magnetic field lines. These studies provide useful insights for understanding the differences in the relative strengths of the instabilities caused by the differing localizations of good and bad magnetic curvature and of the presence of trapped particles. The associated differences in growth rates due to magnetic geometry are large for small values of the temperature gradient parameter n identical to d ln T/d ln n, whereas for large values of n, the mode is strongly unstable for all of the different magnetic geometries.