The Magnetic Response to Sudden Mass-loading of Comet 67P/Churyumov-Gerasimenko’s Induced Magnetosphere

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Martin Volwerk1, Ingo Richter2, Bruce Tsurutani3, Charlotte Goetz2, Kathrin Altwegg4, Thomas W Broiles5, James L Burch5, Chris Carr6, Emanuele Cupido7, Magda Delva8, Melinda Dosa9, Niklas J. T. Edberg10, Anders I Eriksson10, Henri Pierre11, Christoph Koenders12, Jean-Pierre Lebreton13, Kathleen Mandt5, Hans Nilsson14, Andrea Opitz9, Martin Rubin4, Konrad Schwingenschuh15, Gabriella Stenberg Wieser14, Karoly Szego16, Claire Vallat17, Xavier Vallières18 and Karl-Heinz Glassmeier2, (1)Austrian Academy of Sciences, Vienna, Austria, (2)Technical University of Braunschweig, Braunschweig, Germany, (3)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (4)University of Bern, Bern, Switzerland, (5)Southwest Research Institute, San Antonio, TX, United States, (6)Imperial College, London, United Kingdom, London, United Kingdom, (7)Imperial College London, London, United Kingdom, (8)Space Research Institute, Austrian Academy of Sciences, Graz, Austria, (9)Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary, (10)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden, (11)Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, Orleans, France, (12)TU Braunschweig, Braunschweig, Germany, (13)University of Orleans, Orleans, France, (14)IRF Swedish Institute of Space Physics Kiruna, Kiruna, Sweden, (15)Austrian Academy of Sciences, Graz, Austria, (16)Hungarian Academy of Sciences, Budapest, Hungary, (17)ESAC, Villanueva, Spain, (18)Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E) - CNRS - Université d'Orléans, Orléans, France
On 6 June 2015 around 1500 UT there is a sudden increase in ion density and energy in the vicinity of 67P/CG, most likely from an outburst on the surface of the nucleus. The induced magnetosphere around 67P/CG reacts to this sudden mass loading: first there is an increase in the total magnetic field strength and an increase in fluctuations. Low frequency oscillations (f ≤ 10 mHz) are observed. In the early hours 0000 – 0400 UT of 7 June 2015 the plasma density returns to its pre-outburst value, and the magnetic field strength also returns, however the fluctuations in the magnetic field remain strong. Structures reminiscent of mirror mode waves- strong decreases in Bmag associated with strong Langmuir probe currents (proxy for density) – have also been detected starting at 2300 UTC 6 June and seem to evolve into structures with one steeper side. Wavelet analysis over the whole event shows that below 20 mHz there are several dominant frequencies, but different magnetic field components have different spectral content, implying strong polarization of the waves/oscillations.