The mechanism of rf-driven currents by high frequency electromagnetic waves is discussed. It is shown that the current will be driven both by the electric force and Lorentz force, and either the resonant effects or the nonresonant effects may be domi-nant,and there exist some differences between the l0 resonances. It is also shown that under some conditions the collisional power dissipation may be stronger than the resonant power dissipation.