Global ballooning instabilities in a Heliotron J plasma

The global ballooning stability in a Heliotron J plasma [M. Wakatani et al., Nucl. Fusion 40, 569 (2000)] is studied by use of the CAS3D code (code for analysis of stability in three-dimensional systems) [C. Schwab, Phys. Fluids 5, 3195 (1993)]. The global mode has strong toroidal mode coupling so that the mode structure is typically a helical type. The mode structure of the pressure driven modes, including the interchange mode, is discussed. The comparison between the local and global modes is also shown. The eigenvalue as well as eigenfunction shows good agreement.