In the regular experiments carried out with the RAS radio telescopes at Pushchino during 1999-2002, the study of the radial dependence of scattering of compact natural radio sources was extended to remote regions of the solar plasma environment. A vast statistical database was accumulated. The analysis of the data shows that, in addition to the well-known transonic acceleration region at a distance of 10-40 Rs from the Sun, a secondary acceleration region exists at 34-60 Rs, being due to the coincidence of the solar wind and Alfven velocities. The stream in the transalfvenic region displays the same typical radial structure as observed in the transonic region, i.e., the existence of a "precursor" - a narrow band of reduced scattering preceding a wide region of enhanced scattering. It implies that the main features of resonance acceleration of the solar wind streams are conserved at the distances of the order of 60 Rs.