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Origin of the extended Mars radar blackout of September 2017

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journal contribution
posted on 29.05.2019, 14:34 by B Sanchez-Cano, P-L Blelly, M Lester, O Witasse, M Cartacci, R Orosei, H Opgenoorth, R Lillis, F Leblanc, S Milan, P Conroy, N Floury, J Plane, A Cicchetti, R Noschese, A Kopf
The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board Mars Express, which operates between 0.1 and 5.5 MHz, suffered from a complete blackout for 10 days in September 2017 when observing on the nightside (a rare occurrence). Moreover, the Shallow Radar (SHARAD) onboard the Mars Reconnaissance Orbiter, which operates at 20 MHz, also suffered a blackout for 3 days when operating on both day and nightsides. We propose that these blackouts are caused by solar energetic particles (SEP) of few tens of keV and above associated with an extreme space weather event between 10 and 22 September 2017, as recorded by the MAVEN mission. Numerical simulations of energetic electron precipitation predict that a lower O2+ nighttime ionospheric layer of magnitude ~1010 m-3 peaking at ~90 km altitude is produced. Consequently, such a layer would absorb radar signals at HF frequencies and explain the blackouts. The peak absorption level is found to be at 70km altitude.

Funding

B.S.-C., M.L. and S.E.M. acknowledge support through STFC grant ST/N000749/1. ESA-ESTEC Faculty is gratefully acknowledged. F.L. was supported by CNES "Système Solaire” program and by the Programme National de Planétologie and by the ANR (ANR-09-BLAN-0223) and ANR MARMITE (ANR-13-BS05-0012-02). IPIM model simulations can be freely requested at IRAP391 CDPP web (http://transplanet.irap.omp.eu/). IPIM model is a property of CNRS. Part of this work and IPIM are supported by the Programme National Soleil Terre (PNST) from Institut des Sciences de l'Univers of Centre National de la Recherche Scientifique (INSU/CNRS) co-funded by CNES. This work was granted access to the HPC resources of CALMIP supercomputing center under the allocation 2017-P1520.

History

Citation

Journal of Geophysical Research: Space Physics, 2019

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

AM (Accepted Manuscript)

Published in

Journal of Geophysical Research: Space Physics

Publisher

American Geophysical Union (AGU), Wiley

issn

2169-9402

Acceptance date

03/05/2019

Copyright date

2019

Available date

29/05/2019

Publisher version

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018JA026403

Notes

MEX data can be downloaded from the ESA-PSA archive, and MRO and MAVEN data from the NASA-PDS archive.

Language

en