�п���˶�ά�ֲ�ģ�ĵ�������������

Third kind ballooning theory of two dimensional tokamak local modes

The ballooning theory of the third kind is constructed in parallel to the ballooning theory of the first and the second kind by making use of the 2-D ballooning representation. Compared to the ballooning theory of the first kind, the restriction to applicability due to solvability condition is found greatly relaxed to wider parameter domain; and compared to the ballooning theory of the second kind, the solution with higher growth rate is obtained because the destabilization from “bad curvature” is well included within the framework of the theory, which in turn, makes the numerical results more comparable with those from initial value simulations. The fluid model equation for ion temperature gradient mode in toroidal coordinate is adopted to calculate growth rate and eigen frequency as well for selected profile parameters. The results are presented graphically, compared and discussed with the two previous ballooning theories; also discussed is the implication with regard to improved confinement in tokamaks.