Turbulent interstellar plasma and ultrahigh angular resolution in radio astronomy

The effects of the modulation of radio waves during their passage through turbulent interstellar plasma on measurements of the structure of radio sources made with ultrahigh angular resolution using space radio interferometers are considered. Typical scattering angles?_{scat, pl} for an extragalactic radio source at various wavelengths are estimated from scattering observations for pulsars and extragalactic sources. The (?₀λ) plane, where ?₀ is the source size and λ is the wavelength of the radio emission, can be divided into five regions, in which different regimes of radio-wave modulation and image reconstruction are realized. Possibilities for image reconstruction in each of these regions are investigated.