Interplanetary Magnetic Field

Ulysses Radio Tracking from High Solar Latitudes and the Interplanetary Magnetic Field Topology

"Snapshot" of the spiral shape of the interplanetary magnetic field, as obtained from radio observations from the interplanetary spacecraft Ulysses. This view from the north ecliptic pole is based on Ulysses radio measurements made as it was passing over the Sun's south pole. The white symbols represent the actual observations of the location of outward moving streams of electrons, ejected from the Sun on Oct. 25 and Oct. 30, 1994. The numbers indicate the frequency of radio emission, so that "740" represents emission at a radio frequency of 740 kilohertz. The planets Mercury, Venus, and Earth are shown in their approximate true positions at the time of observation; the large orange circles illustrate their orbits around the Sun. A yellow arrow points out the location of the Sun where a solar flare explosion at 10:15 UT on October 25, 1994 ejected the electrons tracked by Ulysses on that date. The spiral blue lines illustrate the shape of the magnetic field as predicted from theory for a constant solar wind speed. PHOTO CREDIT: NASA's Goddard Space Flight Center.