P31E-2095
Evidence of Inhomogeneous Coma Composition at 67P/Churyumov-Gerasimenko
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Charlotte Goetz1, Steven J Schwartz2, Christoph Koenders1,3, Thomas W Broiles4, James L Burch4, Chris Carr5, Emanuele Cupido2, Anders I Eriksson6, Marina F Galand2, Ray Goldstein4, Prachet Mokashi7, Hans Nilsson8, Ingo Richter1, Karoly Szego9, Claire Vallat10, Martin Volwerk11 and Karl-Heinz Glassmeier1, (1)Technical University of Braunschweig, Braunschweig, Germany, (2)Imperial College London, London, United Kingdom, (3)TU Braunschweig, Braunschweig, Germany, (4)Southwest Research Institute, San Antonio, TX, United States, (5)Imperial College, London, United Kingdom, London, United Kingdom, (6)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden, (7)Southwest Research Institute San Antonio, San Antonio, TX, United States, (8)IRF Swedish Institute of Space Physics Kiruna, Kiruna, Sweden, (9)Hungarian Academy of Sciences, Budapest, Hungary, (10)ESAC, Villanueva, Spain, (11)Austrian Academy of Sciences, Vienna, Austria
Abstract:
Since its arrival at comet 67P/Churyumov-Gerasimenko, the instruments of the Rosetta Plasma Consortium (RPC) have been collecting data on an ever growing plasma interaction region around the comet. During the first phase of the mission, this region was dominated by solar wind signatures interspersed with low-frequency magnetic field waves and ion deflection due to heavy cometary ion pick-up. However starting in March 2015, the plasma region became more active with magnetic field strengths around 40-50nT and a number of field discontinuities with ΔB~40nT. This study is aimed at two events in April and May 2015, where the discontinuities were accompanied by a marked change in ion and/or electron flow direction. We propose that this is due to an inhomogeneous composition of the coma that leads to different magnetic field regions, which are triggered by the solar wind, containing different particle populations. These different populations are either the result of a high neutral density or a heightened ionization rate upstream of the spacecraft. In this multi-instrument study we also investigate the influence of charged dust grains, which might influence the electron density.
