Terrestrial 2fp radio source location determined from WIND/GEOTAIL triangulation

We combine simultaneous WIND/GEOTAIL direction‐finding analyses of terrestrial 2fp radio emission to provide the first 3‐D source location by two spacecraft triangulation. These observations were made when WIND and GEOTAIL were relatively close to the electron foreshock and to each other. For two cases presented the 2fp radio source centroid was stationary and located in the upstream wing of the electron foreshock region some 15‐50RE from the contact point. In a third case the 2fp source centroid followed the change in orientation of the electron foreshock.