Formation of a steady supersonic solar wind flow

Abstract

A consistent study of the solar wind has been extended to a wide region of interplanetary space, up to distances from the Sun R ⩾ 90 R _s . Experiments are carried out with the radio telescopes of the Pushchino Radio Astronomy Observatory (Astrospace Center, Lebedev physical Institute, Russian Academy of Sciences): DKR-1000 (λ ≈ 2.7–2.9 m) and RT-22 (λ ≈ 1.35 cm), respectively. The radio-wave scattering characteristics, the scattering angle θ(R) and the scintillation index m(R), are studied. The formation of a steady supersonic solar wind is associated with a sequence of four stages whose scale in different solar wind streams changes within the range 10–23 R _s , depending on the initial stream speed. These circumstances should be taken into account when predicting the state of the near space using data on the solar wind in regions of the interplanetary medium close to the Sun.