Plasma density structures at comet 67P/Churyumov–Gerasimenko

I.A.D Engelhardt (1) , A.I Eriksson (2) , G. Stenberg Wieser (1) , C. Goetz (3) , M. Rubin (4) , Pierre Henri (5) , H. Nilsson (2) , E. Odelstad (6) , Rajkumar Hajra (5) , Xavier Vallières (5)

1 IRF - Swedish Institute of Space Physics [Kiruna]
2 IRF - Swedish Institute of Space Physics [Uppsala / Kiruna]
3 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
4 Physikalisches Institut [Bern]
5 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
6 Department of Physics and Astronomy [Uppsala]

We present a Rosetta Plasma Consortium (RPC) case study based on four events in 2015 autumn at various radial distances, phase angles and local times, just after the perihelion of comet 67P/Churyumov–Gerasimenko. Pulse-like (high-amplitude, up to minutes in time) signatures are seen with several RPC instruments in the plasma density (with the LAngmuir Probe, LAP and Mutual Impedance Probe, MIP), ion energy and flux (with the Ion Composition Analyzer, ICA) and the magnetic field intensity (with the magnetometer, MAG). Furthermore, the cometocentric distance relative to the electron exobase is seen to be a good organizing parameter for the measured plasma variations. The closer Rosetta is to this boundary, the more pulses are measured. This is consistent with the pulses being filaments of plasma originating from the diamagnetic cavity boundary, as predicted by simulations.

Mots clés: plasmas; comets: individual: 67P/Churyumov–Gerasimenko

Domaines: Astrophysique [astro-ph]

I.A.D Engelhardt, A.I Eriksson, G. Stenberg Wieser, C. Goetz, M. Rubin, et al.. Plasma density structures at comet 67P/Churyumov–Gerasimenko. Monthly Notices of the Royal Astronomical Society, 2018, 477 (1), pp.1296-1307. ⟨10.1093/mnras/sty765⟩. ⟨insu-01825180⟩