Small-angle scattering of an extraordinary wave near the upper hybrid resonance

The small-angle scattering of an extraordinary wave by plasma density fluctuations near the upper hybrid resonance is analyzed. It is shown that the efficiency of the small-angle scattering increases markedly as the upper hybrid resonance is approached. The power lost by the probing wave is calculated as a function of distance from the upper hybrid resonance, the parameters of the wavenumber spectrum of density fluctuations, and plasma parameters. The estimates obtained indicate that small-angle scattering, first, may have a strong impact on the experimental results obtained from the enhanced-scattering diagnostic and, second, may be the main cause of the broadening of the frequency spectrum of a signal recorded by this diagnostic technique.