We present the results of the study of scintillations in the circumsol
ar plasma at elongations from 5 to 30 solar radii using occultations o
f water vapor line (lambda = 1.35 cm) maser sources. The results of se
veral sets of experiments conducted in 1991 - 1993 were combined with
previously obtained results in order to study correlations between the
state of the solar supercorona and solar-wind parameters in the forma
tion region of the supersonic plasma outflow.