Influence of Pressure-gradient and Shear on Ballooning Stability in Stellarators

Hudson, S.R. ; Hegna, C.C. ; Nakajima, N.

Princeton University. Plasma Physics Laboratory.

关键词: Ballooning Instabilities;    Stellarators Ballooning Instabilities;    Stability, Ideal Hydromagnetic;    70 Plasma Physics And Fusion Technology;    Polynomials;   

DOI  :  10.2172/837193
RP-ID  :  PPPL-4055
RP-ID  :  AC02-76CH03073
RP-ID  :  837193

美国|英语

来源: UNT Digital Library

【 摘 要 】

Pressure-driven, ideal ballooning stability calculations are often used to predict the achievable plasma in stellarator configurations. In this paper, the sensitivity of ballooning stability to plasmas profile variations is addressed. A simple, semi-analytic method for expressing the ballooning growth rate, for each field line, as a polynomial function of the variation in the pressure gradient and the average magnetic shear from an original equilibrium has recently been introduced [Phys. Plasmas 11:9 (September 2004) L53]. This paper will apply the expression to various stellarator configurations and comment on the validity of various truncated forms of the polynomial expression. In particular, it is shown that in general it is insufficient to consider only the second order terms as previously assumed, and that higher order terms must be included to obtain accurate predictions of stability.