Turbulent interstellar plasma and ultrahigh angular resolution in radio astronomy

The effects of the modulation of radio waves during their passage through t urbulent interstellar plasma on measurements of the structure of radio sour ces made with ultrahigh angular resolution using space radio interferometer s are considered. Typical scattering angles theta (scat,pl) for an extragal actic radio source at various wavelengths are estimated from scattering obs ervations for pulsars and extragalactic sources. The (phi (0),lambda) plane , where phi (0) is the source size and lambda is the wavelength of the radi o 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. (C) 20 01 MAIK "Nauka/Interperiodica".