RPC observation of the development and evolution of plasma interaction boundaries at 67P/Churyumov-Gerasimenko

K. E. Mandt (1, 2) , A. Eriksson (3) , N. J. T. Edberg (3) , C. Koenders (4) , T. Broiles (2) , S. A. Fuselier (2) , C. Goetz (4) , Pierre Henri (5) , Z. Nemeth (6) , M. Alho (7) , N. Biver (8) , A. Beth (9) , J. Burch (2) , C. Carr (10) , K. Chae (2) , A. J. Coates (11, 12) , E. Cupido (10) , M. Galand (9) , R. Goldstein (13) , K.-H. Glassmeier (4) , K. C. Hansen (14) , J. Haiducek (15) , E. Kallio (7) , Jean-Pierre Lebreton (5) , A. Luspay-Kuti (2) , P. Mokashi (2) , H. Nilsson (3) , A. Opitz (16) , I. Richter (4) , M. Samara (13) , K. Szego (6) , C.-Y. Tzou (17) , M. Volwerk (18) , C. Simon Wedlund (19) , G. Stenberg Wieser (3)

1 UTSA Department of Physics and Astronomy [San Antonio]
2 Space Science Division [San Antonio]
3 IRF - Swedish Institute of Space Physics [Uppsala]
4 Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig]
5 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
6 Wigner Research Centre for Physics [Budapest]
7 School of Electrical Engineering [Aalto Univ]
8 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
9 Department of Physics [Imperial College London]
10 Blackett Laboratory
11 MSSL - Mullard Space Science Laboratory
12 CPS - Centre for Planetary Sciences [UCL/Birkbeck]
13 SwRI - Southwest Research Institute [San Antonio]
14 CLaSP - Department of Climate and Space Sciences and Engineering
15 University of Michigan
16 IRAP - Institut de recherche en astrophysique et planétologie
17 WP - Space Research and Planetary Sciences [Bern)
18 IWF - Space Research Institute of Austrian Academy of Sciences
19 Department of Physics [Oslo]

One of the primary objectives of the Rosetta Plasma Consortium, a suite of five plasma instruments on-board the Rosetta spacecraft, is to observe the formation and evolution of plasma interaction regions at the comet 67P/Churyumov-Gerasimenko (67P/CG). Observations made between 2015 April and 2016 February show that solar wind–cometary plasma interaction boundaries and regions formed around 2015 mid-April and lasted through early 2016 January. At least two regions were observed, separated by an ion-neutral collisionopause boundary. The inner region was located on the nucleus side of the boundary and was characterized by low-energy water-group ions, reduced magnetic field pileup and enhanced electron densities. The outer region was located outside of the boundary and was characterized by reduced electron densities, water-group ions that are accelerated to energies above 100 eV and enhanced magnetic field pileup compared to the inner region. The boundary discussed here is outside of the diamagnetic cavity and shows characteristics similar to observations made on-board the Giotto spacecraft in the ion pileup region at 1P/Halley. We find that the boundary is likely to be related to ion-neutral collisions and that its location is influenced by variability in the neutral density and the solar wind dynamic pressure.

Keywords: plasmas; solar wind; comets: general

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]; Physics [physics]; Physics [physics]; Space Physics [physics.space-ph]

K. E. Mandt, A. Eriksson, N. J. T. Edberg, C. Koenders, T. Broiles, et al.. RPC observation of the development and evolution of plasma interaction boundaries at 67P/Churyumov-Gerasimenko. Monthly Notices of the Royal Astronomical Society, 2016, 462 (Suppl 1), pp.S9-S22. ⟨10.1093/mnras/stw1736⟩. ⟨insu-01373688⟩