RPC-IES observations of the development and variability of plasma interaction regions near 67P/Churyumov-Gerasimenko

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Kathleen Mandt1, Stephen A Fuselier2, Christoph Koenders3, Karoly Szego4, Tamas I Gombosi5, Thomas W Broiles2, James L Burch2, Chris Carr6, Anders I Eriksson7, Karl-Heinz Glassmeier3, Pierre Henry8, Hans Nilsson9, Markku Alho10, Kyung Chae2, George B Clark11, Thomas Cravens12, Emanuele Cupido13, Marina F Galand13, Raymond Goldstein2, Jean-Pierre Lebreton14, Prachet Mokashi1, Zoltan Nemeth15, Andrea Opitz16, Craig J Pollock17, Ingo Richter3, Marilia Samara18, Claire Vallat19, Martin Volwerk20, Cyril Wedlund10 and Gabriella Stenberg Wieser9, (1)Southwest Research Institute San Antonio, San Antonio, TX, United States, (2)Southwest Research Institute, San Antonio, TX, United States, (3)Technical University of Braunschweig, Braunschweig, Germany, (4)Hungarian Academy of Sciences, Budapest, Hungary, (5)Univ of Michigan, Ann Arbor, MI, United States, (6)Imperial College, London, United Kingdom, London, United Kingdom, (7)IRF Swedish Institute of Space Physics Uppsala, Uppsala, Sweden, (8)CNRS, Paris Cedex 16, France, (9)IRF Swedish Institute of Space Physics Kiruna, Kiruna, Sweden, (10)Aalto University, Aalto, Finland, (11)Catholic University of America, Washington, DC, United States, (12)University of Kansas, Lawrence, KS, United States, (13)Imperial College London, London, United Kingdom, (14)University of Orleans, Orleans, France, (15)Wigner Research Center for Physics, Budapest, Hungary, (16)Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary, (17)NASA Goddard Space Flight Center, Heliophysics Sci. Div., Greenbelt, MD, United States, (18)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (19)ESAC, Villanueva, Spain, (20)Austrian Academy of Sciences, Vienna, Austria
Spacecraft flybys of comets have provided observations of different solar wind-cometary plasma interaction regions separated by boundaries. Past observations were limited to a few high-velocity flybys, so some regions remain poorly understood. Various modeling techniques provide important insight, but do not answer all questions. One unusual region that is difficult to explain with models is called the “Mystery” region. This region was observed on a few flybys on the sunward side beginning well after the bow shock and terminating with a “Mystery” boundary located halfway between the bow shock and the comet. Within this region there is a significant increase in “hot” electrons (> 800 eV) and solar wind He++. The “Mystery” boundary is characterized by a rapid decrease in hot electrons, solar wind He++, and total ion mass flux, along with an increase in cometary ions. The magnetic field did not vary within this region or across the boundary. Rosetta is uniquely placed to improve understanding of plasma interaction regions because the spacecraft remains close (< 1500 km) to comet 67P for an extended period of time. Recent observations by the Rosetta Plasma Consortium (RPC) Ion Electron Spectrometer (IES) suggest that the spacecraft frequently crosses a boundary between two interaction regions that bears some resemblance to the “Mystery” boundary. The timing and location of these boundary crossings appear to correlate with solar wind activity extrapolated to the Rosetta location, suggesting a complex and dynamic plasma interaction environment.