Stability analysis of ITER plasmas with H-mode profiles

摘要

The ideal MHD stability properties of ITER TAC-4 H-mode profiles are studied. The effects of the current profile variation on the stability of high-n ballooning modes and the n=1 mode are analyzed (n: toroidal mode number). The variation of the current profile is characterized by the change of the safety factor on the magnetic axis, q(sub O), while the total plasma current is fixed. The beta limit of the high-n ballooning modes remains g(sub T)=3.3 for such variations (g(sub T): Troyon's factor). The unstable n=1 mode is strongly localized at the plasma edge (peeling mode) for q(sub O)=1.0 and the beta limit of the n=1 mode is g(sub T)=3.7. In case of q(sub O)<0.9, the stability of the n=1 mode is determined by the internal kink mode and the beta limit is reduced to g(sub T)=2.4 for q(sub O)=0.8. Stability analysis predicts that the H-mode profiles with g(sub T)=3 can be realized when q(sub O) is kept to be greater than 0.9 and the current profile at the edge is fixed. This analysis also shows the stability of the TAC4 H-mode profiles will be sensitive to the edge current profile. (author). (ERA citation 20:014513)