Type III radio source located by Ulysses/Wind triangulation

Abstract

Radio triangulation from the widely separated Ulysses and Wind spacecraft is used to reconstruct the trajectory of a type III radio burst in the three-dimensional heliosphere. The derived radio trajectory follows a (Parker) spiral path corresponding to a solar wind speed of ~200km/s and progresses to the south of the ecliptic plane. These remote radio observations also measure the interplanetary plasma density along the path of the radio source. The derived average density-distance scale is very similar to the previously derived RAE density scale, which was determined in a different way. The results of the radio triangulation combined with a drift rate analysis give an average electron exciter speed of ~0.3c. The radio source size and the brightness temperature as viewed from Ulysses and Wind are determined and compared as a function of observing frequency.