Observations of anisotropic compressive turbulence near the sun

Abstract

Small-scale density-fluctuations cause angular-broadening of distant radio sources observed through the solar wind. Observations of angular broadening near the Sun show that the compressive microstructure is highly field aligned. Recent work strongly suggests that the density fluctuations are caused by obliquely propagating MHD waves. With this in mind we have made a new series of angular scattering observations using the Giant Meter Wavelength Radio Telescope (GMRT) located near Pune. We selected radio sources passing over the solar poles at distances near 10 Rs. By comparing these observations with simultaneous white light scattering from the LASCO C3 instrument, we hoped to learn how the waves are related to the large scale coronal structures, i.e. coronal holes, polar plumes, and streamers.