The development of small-scale irregularities in the ionosphere disturbed by powerful oblique HF radio waves

It is shown that small-scale artificial turbulence develops in the middle latitude ionosphere due to disturbance by a powerful oblique high frequency radio wave. The conclusion is based on experimental data obtained by the method of the aspect-sensitive scattering of the HF wave from inhomogeneities with scales of l⊥∼12 m transverse to the geomagnetic field H̃. This work shows that changes in the amplitude and frequency spectra of the probe waves are correlated with changes in the HF power during ionospheric modification by powerful oblique radio emission. The data obtained provide evidence of strengthening of small-scale non-isotropic fluctuations in electron density for the situation when the interaction of the powerful radio waves with the ionosphere does not have a resonant nature, because in the case of oblique propagation the radio waves are reflected below the level at which the frequency of the wave is equal to the plasma frequency. © 1998 COSPAR. Published by Elsevier Science Ltd