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Ion-temperature-gradient instability in toroidal plasmas

Technical Report ·
DOI:https://doi.org/10.2172/5404094· OSTI ID:5404094

The stability of the ion-temperature-gradient mode in a toroidal plasma is investigated. Using the ballooning-mode formalism, an ordinary difference-differential equation is derived which includes full kinetic effects. The equation is, then, examined in various limits where it reduces to an ordinary differential equation. Analytic and computational studies show that, for eta/sub i/ identical with d lnT/sub i//d lnn > 1, toroidal effects further destabilize the mode and, hence, the corresponding growth rates exceed those obtained from the slab calculations. However, it is also found that toroidal effects give rise to higher eta/sub i/ threshold compared to the slab case. Extensive numerical calculations over a wide range of parameters are carried out to delineate the regions of instability. It is concluded that the eta/sub i/ instability is of relevance to present-day beam heated tokamaks.

Research Organization:
Princeton Univ., NJ (USA). Plasma Physics Lab.
DOE Contract Number:
EY-76-C-02-3073
OSTI ID:
5404094
Report Number(s):
PPPL-1601
Country of Publication:
United States
Language:
English