Birth of a Magnetosphere

Hans Nilsson, Etienne Behar, James L. Burch, Christopher M. Carr, Anders I. Eriksson, Karl Heinz Glassmeier, Pierre Henri, Marina Galand, Charlotte Goetz, Herbert Gunell, Tomas Karlsson

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

4 Citations (Scopus)


A magnetosphere may form around an object in a stellar wind either due to the intrinsic magnetic field of the object or stellar wind interaction with the ionosphere of the object. Comets represent the most variable magnetospheres in our solar system, and through the Rosetta mission we have had the chance to study the birth and evolution of a comet magnetosphere as the comet nucleus approached the Sun. We review the birth of the comet magnetosphere as observed at comet 67P Churyumov-Gerasimenko, the formation of plasma boundaries and how the solar wind-atmosphere interaction changes character as the cometary gas cloud and magnetosphere grow in size. Mass loading of the solar wind leads to an asymmetric deflection of the solar wind for low outgassing rates. With increasing activity a solar wind ion cavity forms. Intermittent shock-like features were also observed. For intermediate outgassing rate a diamagnetic cavity is formed inside the solar wind ion cavity, thus well separated from the solar wind. The cometary plasma was typically very structured and variable. The region of the coma dense enough to have significant collisions forms a special region with different ion chemistry and plasma dynamics as compared to the outer collision-free region.

Original languageEnglish
Title of host publicationMagnetospheres in the Solar System
EditorsRomain Maggiolo, Nicolas André, Hiroshi Hasegawa, Daniel T Welling, Yongliang Zhang, Larry J Paxton
Number of pages13
ISBN (Electronic)9781119815624
ISBN (Print)9781119507529
Publication statusPublished - 23 Apr 2021
Externally publishedYes

Publication series

NameGeophysical Monograph Series
ISSN (Print)0065-8448


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