Interplanetary coronal mass ejection observed at STEREO-A, Mars, comet 67P/Churyumov-Gerasimenko, Saturn, and New Horizons en route to Pluto: Comparison of its Forbush decreases at 1.4, 3.1, and 9.9 AU

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Title: Interplanetary coronal mass ejection observed at STEREO-A, Mars, comet 67P/Churyumov-Gerasimenko, Saturn, and New Horizons en route to Pluto: Comparison of its Forbush decreases at 1.4, 3.1, and 9.9 AU
Authors: Witasse, O
Sanchez-Cano, B
Mays, ML
Kajdic, P
Opgenoorth, H
Elliott, HA
Richardson, IG
Zouganelis, I
Zender, J
Wimmer-Schweingruber, RF
Turc, L
Taylor, MGGT
Roussos, E
Rouillard, A
Richter, I
Richardson, JD
Ramstad, R
Provan, G
Posner, A
Plaut, JJ
Odstrcil, D
Nilsson, H
Niemenen, P
Milan, SE
Mandt, K
Lohf, H
Lester, M
Lebreton, J-P
Kuulkers, E
Krupp, N
Koenders, C
James, MK
Intzekara, D
Holmstrom, M
Hassler, DM
Hall, BES
Guo, J
Goldstein, R
Goetz, C
Glassmeier, KH
Genot, V
Evans, H
Espley, J
Edberg, NJT
Dougherty, M
Cowley, SWH
Burch, J
Behar, E
Barabash, S
Andrews, DJ
Altobelli, N
Item Type: Journal Article
Abstract: We discuss observations of the journey throughout the Solar System of a large interplanetary coronal mass ejection (ICME) that was ejected at the Sun on 14 October 2014. The ICME hit Mars on 17 October, as observed by the Mars Express, Mars Atmosphere and Volatile EvolutioN Mission (MAVEN), Mars Odyssey, and Mars Science Laboratory (MSL) missions, 44 h before the encounter of the planet with the Siding-Spring comet, for which the space weather context is provided. It reached comet 67P/Churyumov-Gerasimenko, which was perfectly aligned with the Sun and Mars at 3.1 AU, as observed by Rosetta on 22 October. The ICME was also detected by STEREO-A on 16 October at 1 AU, and by Cassini in the solar wind around Saturn on the 12 November at 9.9 AU. Fortuitously, the New Horizons spacecraft was also aligned with the direction of the ICME at 31.6 AU. We investigate whether this ICME has a nonambiguous signature at New Horizons. A potential detection of this ICME by Voyager 2 at 110–111 AU is also discussed. The multispacecraft observations allow the derivation of certain properties of the ICME, such as its large angular extension of at least 116°, its speed as a function of distance, and its magnetic field structure at four locations from 1 to 10 AU. Observations of the speed data allow two different solar wind propagation models to be validated. Finally, we compare the Forbush decreases (transient decreases followed by gradual recoveries in the galactic cosmic ray intensity) due to the passage of this ICME at Mars, comet 67P, and Saturn.
Issue Date: 1-Aug-2017
Date of Acceptance: 21-Jun-2017
ISSN: 2169-9380
Publisher: American Geophysical Union
Start Page: 7865
End Page: 7890
Journal / Book Title: Journal of Geophysical Research: Space Physics
Volume: 122
Issue: 8
Copyright Statement: ©2017. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Keywords: Science & Technology
Physical Sciences
Astronomy & Astrophysics
interplanetary coronal mass ejection
Forbush decrease
comet 67P
New Horizons
Publication Status: Published
Open Access location:
Appears in Collections:Space and Atmospheric Physics

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