Fast drift Alfven waves excited at the low-frequency band in tokamak plasmas

It is shown that fast drift Alfven waves can be excited in tokamak plasmas by an external antenna operating in the low-frequency band. The dispersion of these waves depends on the derivative of the q-profile or drift terms in the case of low or negative shear. The wave absorption is determined by the Alfven continuum dissipation and has an oscillating increase with frequency. Typical global Alfven wave resonances are found at the plasma core for different signs of poloidal/toroidal mode numbers (N/M < 0) for a standard tokamak safety factor profile with central value q(0)>1. (C) 2007 American Institute of Physics.