Extension of drift magnetic island theory beyond the common profile function approximation

The approach of several profile functions for studying drift magnetic islan ds is developed. This approach yields more favorable predictions for the ro le of the polarization current than the less adequate approach of a common profile function adopted in preceding studies. It is shown that the polariz ation current is stabilizing not only for subdrift islands propagating in t he ion drift direction but also for islands propagating in the electron dri ft direction with a sufficiently low rotation frequency. (C) 2000 American Institute of Physics. [S1070-664X(00)00111-4].