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Kansans contribute papers on the heliosphere to international science journal
July 24, 2008
Studying data streamed back from the Voyager 2 spacecraft, Dr. Thomas Armstrong, Fundamental Technologies, Lawrence, co-authored a paper included as one of the articles for a lead feature “Voyages to the Heliosphere” in the July 3, 2008, issue of Nature. Lead author of the paper was University of Kansas alumnus Dr. Robert Decker of Johns Hopkins University Applied Physics Lab.
The solar system is not round, but rather asymmetric and squashed, according to information received from the Voyager 2 spacecraft last August. The Nature articles analyze recent observations from the edge of the solar system and give a picture of how our Sun interacts with the rest of the galaxy.
Launched in 1977, the two Voyager probes long ago completed their missions to fly by Jupiter and Saturn and have continued on to the farthest reaches of our solar system. Powered by long-life nuclear batteries in the absence of solar energy, the probes are still sending back data after more than 30 years.
The current mission of both spacecraft is to reach and study the outer limits of the heliosphere, a magnetic ‘bubble’ around the solar system created by the solar wind, a stream of ions that constantly flows outward from the Sun. The transition zone between it and the rest of interstellar space is known as ‘termination shock’.
Because the Voyager spacecraft were each sent different directions and Voyager 2 crossed this boundary closer to the sun than its twin, it appears that the heliosphere in this region is dented, or pushed in, closer to the Sun by a local magnetic field. Companion papers explore more details, analyzing magnetic field, plasma-wave and lower-energy particle observations. Decker, Armstrong and their colleagues studied the changes in electron and ion intensity observed by Voyager 2. They suggest that acceleration of ions extracts a large fraction of bulk-flow kinetic energy from the solar wind.
Source: Nature press release.