Annales Geophysicae (Aug 2015)
Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko
- I. Richter,
- C. Koenders,
- H.-U. Auster,
- D. Frühauff,
- C. Götz,
- P. Heinisch,
- C. Perschke,
- C. Perschke,
- U. Motschmann,
- U. Motschmann,
- B. Stoll,
- K. Altwegg,
- J. Burch,
- C. Carr,
- E. Cupido,
- A. Eriksson,
- P. Henri,
- R. Goldstein,
- J.-P. Lebreton,
- P. Mokashi,
- Z. Nemeth,
- H. Nilsson,
- M. Rubin,
- K. Szegö,
- B. T. Tsurutani,
- C. Vallat,
- M. Volwerk,
- K.-H. Glassmeier
Affiliations
- I. Richter
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- C. Koenders
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- H.-U. Auster
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- D. Frühauff
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- C. Götz
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- P. Heinisch
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- C. Perschke
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- C. Perschke
- Institut für Theoretische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- U. Motschmann
- Institut für Theoretische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- U. Motschmann
- German Aerospace Center (DLR), Institute of Planetary Research, Rutherfordstraße 2, 12489 Berlin, Germany
- B. Stoll
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- K. Altwegg
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
- J. Burch
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510, USA
- C. Carr
- Imperial College London, Exhibition Road, London SW7 2AZ, UK
- E. Cupido
- Imperial College London, Exhibition Road, London SW7 2AZ, UK
- A. Eriksson
- Swedish Institute of Space Physics, Ångström Laboratory, Lägerhyddsvägen 1, Uppsala, Sweden
- P. Henri
- Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, UMR 7328 CNRS – Université d'Orléans, Orléans, France
- R. Goldstein
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510, USA
- J.-P. Lebreton
- Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, UMR 7328 CNRS – Université d'Orléans, Orléans, France
- P. Mokashi
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228-0510, USA
- Z. Nemeth
- Wigner Research Centre for Physics, 1121 Konkoly Thege Street 29–33, Budapest, Hungary
- H. Nilsson
- Swedish Institute of Space Physics, P.O. Box 812, 981 28 Kiruna, Sweden
- M. Rubin
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
- K. Szegö
- Wigner Research Centre for Physics, 1121 Konkoly Thege Street 29–33, Budapest, Hungary
- B. T. Tsurutani
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
- C. Vallat
- Rosetta Science Ground Segment, European Space Astronomy Centre, 28691 Villanueva de la Cañada, Madrid, Spain
- M. Volwerk
- Space Research Institute, Austrian Academy of Sciences, Schmiedlstraße 6, 8042 Graz, Austria
- K.-H. Glassmeier
- Institut für Geophysik und extraterrestrische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
- DOI
- https://doi.org/10.5194/angeo-33-1031-2015
- Journal volume & issue
-
Vol. 33
pp. 1031 – 1036
Abstract
We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko in its low-activity state. Quasi-coherent, large-amplitude (δ B/B ~ 1), compressional magnetic field oscillations at ~ 40 mHz dominate the immediate plasma environment of the nucleus. This differs from previously studied cometary interaction regions where waves at the cometary ion gyro-frequencies are the main feature. Thus classical pickup-ion-driven instabilities are unable to explain the observations. We propose a cross-field current instability associated with newborn cometary ion currents as a possible source mechanism.
