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B Sanchez-Cano
B
Sanchez-Cano
P-L Blelly
P-L
Blelly
M Lester
M
Lester
O Witasse
O
Witasse
M Cartacci
M
Cartacci
R Orosei
R
Orosei
H Opgenoorth
H
Opgenoorth
R Lillis
R
Lillis
F Leblanc
F
Leblanc
S Milan
S
Milan
P Conroy
P
Conroy
N Floury
N
Floury
J Plane
J
Plane
A Cicchetti
A
Cicchetti
R Noschese
R
Noschese
A Kopf
A
Kopf
Origin of the extended Mars radar blackout of September 2017
University of Leicester
2019
Mars’ ionosphere
radar blackout
electron precipitation
space weather
solar energetic particles
2019-05-29 14:34:38
Journal contribution
https://figshare.le.ac.uk/articles/journal_contribution/Origin_of_the_extended_Mars_radar_blackout_of_September_2017/10225820
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.