Numerical study of anomalous absorption of O mode waves on magnetic field‐aligned striations

Simple expressions that describe mode conversion and anomalous absorption of ordinary (O) mode waves injected at angles between the vertical and magnetic zenith to upper hybrid (UH) oscillations in the presence of field‐aligned density striations are presented. The absorption takes place in a region above the UH resonance layer where the striations allow trapped eigenmodes, leading to excitation of large‐amplitude UH waves. The derivation of the expressions is guided by dimensional analysis and numerical simulations. The results are relevant in interpreting high‐latitude heating experiments where anomalous absorption due to striations plays a crucial role.