@article{66e9a1c467a24cf0ad3c2f525d0bd980,
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",
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.",
keywords = "comet 67P, Forbush decrease, interplanetary coronal mass ejection, Mars, New Horizons, Saturn",
author = "O. Witasse and B. S{\'a}nchez-Cano and Mays, {M. L.} and P. Kajdi{\v c} and H. Opgenoorth and Elliott, {H. A.} and Richardson, {I. G.} and I. Zouganelis and J. Zender and Wimmer-Schweingruber, {R. F.} and L. Turc and Taylor, {M. G.G.T.} and E. Roussos and A. Rouillard and I. Richter and Richardson, {J. D.} and R. Ramstad and G. Provan and A. Posner and Plaut, {J. J.} and D. Odstrcil and H. Nilsson and P. Niemenen and Milan, {S. E.} and K. Mandt and H. Lohf and M. Lester and Lebreton, {J. P.} and E. Kuulkers and N. Krupp and C. Koenders and James, {M. K.} and D. Intzekara and M. Holmstrom and Hassler, {D. M.} and Hall, {B. E.S.} and J. Guo and R. Goldstein and C. Goetz and Glassmeier, {K. H.} and V. G{\'e}not and H. Evans and J. Espley and Edberg, {N. J.T.} and M. Dougherty and Cowley, {S. W.H.} and J. Burch and E. Behar and S. Barabash and Andrews, {D. J.} and N. Altobelli",
note = "Funding Information: B.S-.C., G.P., S.E.M., M.L., M.K.J., S.W.H.C., and B.E.S.H acknowledge support through STFC grants ST/K001000/1, ST/N000749/1, and ST/K502121/1. M.L.M. and I.G.R. acknowledge the support of NASA LWS grants NNX15AB80G and NNG06EO90A, respectively. Simulation results have been provided by the Community Coordinated Modeling Center at the Goddard Space Flight Center through their public Runs on Request system (http://ccmc.gsfc.nasa.gov; run numbers Leila_Mays_092716_SH_1 and Leila_Mays_100116_SH_1). The WSA model was developed by N. Arge at AFRL, and the ENLIL model was developed by D. Odstrcil at GMU. P.K.{\textquoteright}s work has been supported by the Programa de Apoyo a Proyectos de Investigaci{\'o}n e Innovaci{\'o}n Tecnol{\'o}gica grant IA104416. J.D.R. was supported by NASA{\textquoteright}s Voyager project. N.J.T.E. was funded by the Swedish National Space Board (135/13) and The Swedish Research Council (621-2013-4191). The Propagation Tool is designed and developed by the CDPP and GFI under CNES funding; it can be accessed from http://propagationtool.cdpp.eu/. All the MAVEN, MSL, Mars Odyssey, Cassini, and New Horizons data sets are available at the NASA PDS. All the scientific data from Mars Express are available at the ESA PSA and AMDA (http://amda.cdpp. eu/). The Propagation Tool, 3DView, and AMDA analysis systems are designed and provided by the Centre de Donn{\'e}es de la Physique des Plasmas (CDPP) supported by CNRS, CNES, Observatoire de Paris, and Universit{\'e} Paul Sabatier, Toulouse. The Propagation Tool is developed by GFI and can be accessed from http://propagationtool.cdpp.eu/. Rosetta scientific data sets are available at the ESA PSA and Rosetta SREM data at http://spitfire.estec.esa.int/sedat/ dplot_odi.html. All the solar data are available at https://sohodata.nascom. nasa.gov/cgi-bin/data_query, http:// sdo.gsfc.nasa.gov/data/aiahmi/, https:// stereo-ssc.nascom.nasa.gov/beacon/ beacon_secchi.shtml, and http:// proba2.sidc.be/data/LYRA. Voyager 2 data are available at http://web.mit.edu/ space/www/voyager/voyager.html and http://voyager.gsfc.nasa.gov/heliopause/data.html. The Bartol Research Institute neutron monitor program is supported by the National Science Foundation under grants PLR-1245939 and PLR-1341562, and by the University of Delaware Department of Physics and Astronomy and Bartol Research Institute, and can be downloaded from http://neutronm.bartol.udel.edu/. Very useful discussions within the Mars Upper Atmosphere Network (MUAN) and support from the ESA-ESTEC Faculty are acknowledged. Useful discussions with Michel Denis and Martin Shaw Publisher Copyright: {\textcopyright}2017. The Authors.",
year = "2017",
month = aug,
doi = "10.1002/2017JA023884",
language = "English",
volume = "122",
pages = "7865--7890",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9380",
publisher = "American Geophysical Union",
number = "8",
}