  The local stability of ion-temperature gradient driven mode (ITG) in the
presence of a given radial electric field is investigated using gyrokinetic
theory and ballooning mode formalism with toroidal effect accounted for. It is
found that, zero frequency radial electric field induced poloidal rotation can
significantly stabilize ITG, while the associated density perturbation has
little effect on ITG stability due to the modification of finite-orbit-width
effect. However, the parallel mode structure is slightly affected due to the
evenly symmetric density modulation of ZFZF.
