More on core-localized toroidal Alfven eigenmodes

摘要

A novel type of ideal toroidal Alfven eigenmode, localized in the low-shear core region of a tokamak plasma, is shown to exist, whose frequency is near the upper continuum of the toroidal Alfven gap. This mode converts to a kinetic-type toroidal Alfven eigenmode above a critical threshold that depends on aspect ratio, pressure gradient, and shear. Opposite to the usual ideal toroidal Alfven eigenmode, this new mode is peaked in amplitude on the small-major-radius side of the plasma.