Skip to Main content Skip to Navigation
Journal articles

First detection of a diamagnetic cavity at comet 67P/Churyumov-Gerasimenko

Abstract : Context: The Rosetta magnetometer RPC-MAG has been exploring the plasma environment of comet 67P/Churyumov-Gerasimenko since August 2014. The first months were dominated by low-frequency waves which evolved into more complex features. However, at the end of July 2015, close to perihelion, the magnetometer detected a region that did not contain any magnetic field at all. Aims: These signatures match the appearance of a diamagnetic cavity as was observed at comet 1P/Halley in 1986. The cavity here is more extended than previously predicted by models and features unusual magnetic field configurations, which need to be explained Methods: The onboard magnetometer data were analyzed in detail and used to estimate the outgassing rate. A minimum variance analysis was used to determine boundary normals. Results. Our analysis of the data acquired by the Rosetta Plasma Consortium instrumentation confirms the existence of a diamagnetic cavity. The size is larger than predicted by simulations, however. One possible explanation are instabilities that are propagating along the cavity boundary and possibly a low magnetic pressure in the solar wind. This conclusion is supported by a change in sign of the Sun-pointing component of the magnetic field. Evidence also indicates that the cavity boundary is moving with variable velocities ranging from 230−500 m/s.
Document type :
Journal articles
Complete list of metadatas

Cited literature [15 references]  Display  Hide  Download
Contributor : Nathalie Rouchon <>
Submitted on : Thursday, May 19, 2016 - 11:38:11 AM
Last modification on : Thursday, September 17, 2020 - 12:29:55 PM


Publisher files allowed on an open archive




C Goetz, C Koenders, I Richter, Kathrin Altwegg, J Burch, et al.. First detection of a diamagnetic cavity at comet 67P/Churyumov-Gerasimenko. Astronomy and Astrophysics - A&A, EDP Sciences, 2016, 588, pp.A24. ⟨10.1051/0004-6361/201527728⟩. ⟨insu-01318108⟩



Record views


Files downloads