Solar wind : structure and dynamics

Abstract

The interplanetary scintillation (IPS) observations can be used for the determination of structure and dynamics of the solar wind. The parameters of the plasma irregularities of the solar wind are usually derived by investigating the interplanetary scintillation observations in the light of scattering theories. Here we present a case study of parameter estimation using diffractive-refractive scattering approach. Solar wind speed at the point of closest approach of Sun to the radio source-observer line can be estimated using three station as well as single station IPS observations. Using the 'garden hose' model of solar plasma flow in the interplanetary medium, an improved scheme of back-projection of solar wind speed to its origin in the solar corona is proposed. The scheme provides estimation of solar plasma acceleration in the inner heliosphere. Here typical solar plasma acceleration results for 1987-88 are also presented and discussed. The solar plasma acceleration is found to vary from ~4 meters/sec. to the power2 to 23 meters/sec. to the power 2