Surface instability of a current carrying plasma under the influence of a high frequency electric field

Surface instability of a collisionless semi-infinite current carrying plasma is studied. The semi-infinite plasma bounded by a plane surface is under the influence of a high frequency (HF) field. There are two classes of surface modes. One is a normal extension of zero high frequency field and the other due entirely to the presence of HF field. As expected, with the increase in the HF field, the growth rates of the surface instabilities decrease. There are regions defined by the electronic drift velocity u where the unstable surface and bulk regions overlap. The interesting result is that unlike the bulk plasma, there is stable region on the u-axis flanked by two unstable regions. The width of this stable region increases with the increase in the field strength. (author)