Interplanetary disturbances and their association with large-scale magnetic field on the sun

Abstract

The principal purpose of this paper is to review recent progress in the study of three-dimensional aspects of interplanetary disturbances on the basis of interplanetary scintillation measurements. The scintillation technique exploits the scattering of radio waves from distant cosmic sources by the density turbulence in the solar wind and interplanetary disturbances are identified by the increase in the level of density turbulence compared with the ambient solar wind. In the present study, scintillation observations obtained within 1 AU using the Ooty Radio Telescope have been analyzed to study a large number of disturbances between minimum (August 1986) and maximum (April 1991) of the previous solar cycle. The spatial and dynamical distribution of these disturbances are compared with results from the Solar Maximum Mission (SMM) K-corona data and other solar measurements. The results indicate that most of the disturbances are associated with active prominences on the sun, which are suggested to be the source of coronal mass ejections (CMEs).