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The Impact of Energ...
The Impact of Energetic Particles on the Martian Ionosphere During a Full Solar Cycle of Radar Observations: Radar Blackouts
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- Lester, Mark (author)
- School of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
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- Sanchez-Cano, Beatriz (author)
- School of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
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- Potts, Daniel (author)
- School of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
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- Lillis, Rob (author)
- Space Sciences Laboratory, University of California, CA, Berkeley, United States
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- Cartacci, Marco (author)
- Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica, Rome, Italy
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- Bernardini, Fabrizio (author)
- Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica, Rome, Italy
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- Orosei, Roberto (author)
- Istituto di Radioastronomia, Istituto Nazionale di Astrofisica, Bologna, Italy
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- Perry, Matthew (author)
- Planetary Science Institute, CO, Lakewood, United States
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- Putzig, Nathaniel (author)
- Planetary Science Institute, CO, Lakewood, United States
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- Campbell, Bruce (author)
- Center for Earth and Planetary Studies, Smithsonian Institution, DC, Washington, United States
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- Blelly, Pierre-Louis (author)
- Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
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- Milan, Steve (author)
- School of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
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- Opgenoorth, Hermann J. (author)
- Umeå universitet,Institutionen för fysik,School of Physics and Astronomy, University of Leicester, Leicester, United Kingdom
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- Witasse, Olivier (author)
- European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands
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- Redrojo, Elena M. M. (author)
- Valquer Laboratorios, Villaminaya, Spain
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- Russell, Aaron (author)
- Planetary Science Institute, CO, Lakewood, United States
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(creator_code:org_t)
- John Wiley & Sons, 2022
- 2022
- English.
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In: Journal of Geophysical Research - Space Physics. - : John Wiley & Sons. - 2169-9380 .- 2169-9402. ; 127:2
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https://doi.org/10.1...
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https://umu.diva-por... (primary) (Raw object)
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Abstract
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- We present the first long-term characterization of ionization layers in the lower ionosphere of Mars (below ∼90 km), a region inaccessible to orbital in-situ observations, based on an analysis of radar echo blackouts observed on Mars Express and the Mars Reconnaissance Orbiter from 2006 to 2017. A blackout occurs when the expected surface reflection is partly or totally attenuated for portions of an observation. Enhanced ionization at altitudes of 60–90 km, below the main ionospheric electron density peak, leads to increased absorption of the radar signal, resulting in the blackouts. We find that (a) MARSIS, operating at frequencies between 1.8 and 5 MHz, suffered more blackouts than SHARAD, which has a higher carrier frequency (20 MHz), (b) there is a clear correlation of blackout occurrence with solar cycle, (c) there is no apparent relationship between blackout occurrence and crustal magnetic fields, and (d) blackouts occur during both nightside and dayside observations, although the peak occurrence is deep on the nightside. Analysis of Mars Atmosphere and Volatile EvolutioN Solar Energetic Particle electron counts between 20 and 200 keV demonstrates that these electrons are likely responsible for attenuating the radar signals. We investigate the minimum SEP electron fluxes required to ionize the lower atmosphere and produce measurable attenuation. When both radars experience a blackout, the SEP electron fluxes are at their highest. Based on several case studies, we find that the average SEP spectrum responsible for a blackout is particularly enhanced at its higher energy end, that is, above 70 keV.
Subject headings
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
- NATURVETENSKAP -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)
Keyword
- Mars express
- Mars ionosphere
- Mars reconnaissance orbiter
- radio sounding
- solar energetic particles
- the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission
Publication and Content Type
- ref (subject category)
- art (subject category)
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- By the author/editor
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Lester, Mark
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Sanchez-Cano, Be ...
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Potts, Daniel
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Lillis, Rob
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Cartacci, Marco
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Bernardini, Fabr ...
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show more...
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Orosei, Roberto
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Perry, Matthew
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Putzig, Nathanie ...
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Campbell, Bruce
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Blelly, Pierre-L ...
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Milan, Steve
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Opgenoorth, Herm ...
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Witasse, Olivier
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Redrojo, Elena M ...
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Russell, Aaron
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- About the subject
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Physical Science ...
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and Astronomy Astrop ...
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- NATURAL SCIENCES
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NATURAL SCIENCES
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and Physical Science ...
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and Fusion Plasma an ...
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Journal of Geoph ...
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Umeå University