Large ponderomotive forces can occur near a high‐power ion cyclotron range of frequency antenna, particularly for the parallel electric field polarization used to excite ion‐Bernstein waves (IBW). The magnetohydrodynamic (MHD) equilibrium of the edge plasma is modified by these forces when the antenna is highly localized poloidally and toroidally. Magnetic islands develop at the edge, nearq=m/n, where ‖m‖≤&pgr;a/waand ‖n‖≤&pgr;R/la, withwaandlathe width and length of the antenna, respectively. Ergodicity of the magnetic field lines may be expected when the islands overlap. Numerical calculations of the island overlap criteria are presented for two examples relevant to present day (IBW) heating experiments.