Solar Wind Speed Azimuthal Variation Along the Heliospheric Current Sheet

Abstract

We report on analysis of the speeds measured by Voyager 1 and 2 while skimming along a horizontal (east-west) portion of the current sheet over several days in 1977. The results demonstrate that in this case speed variations exist and are large enough to significantly deform the sheet within a few AU or less if the current sheet were anything but perfectly horizontal. The spatial scale of the speed variation ranges from the smallest measureable scale using 1 hour averaged data up to tens of degrees in longitude. A deformation example is given under the assumption that the observed velocity variation exists on a current sheet that is initially perpendicular to the heliographic equator.