Oblique Reflections of Mars Express MARSIS Radar Signals From Ionospheric Density Structures: Raytracing Analysis
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10405824" target="_blank" >RIV/00216208:11320/19:10405824 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=9XC73sT9ET" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=9XC73sT9ET</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1029/2018JE005891" target="_blank" >10.1029/2018JE005891</a>
Alternative languages
Result language
angličtina
Original language name
Oblique Reflections of Mars Express MARSIS Radar Signals From Ionospheric Density Structures: Raytracing Analysis
Original language description
Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) radar sounder on board the Mars Express spacecraft revealed oblique reflections coming systematically from apparently stable density structures in the Martian ionosphere. Although these were typically interpreted by assuming a straight line propagation of the sounding signal at the speed of light, the ionospheric plasma is clearly a dispersive medium. Consequently, the ray propagation paths may be significantly bent, and, moreover, the observed time delays need to be interpreted in terms of realistic group velocities of the signal propagation. We select a single particularly well-pronounced event with oblique reflections observable over a large range of signal frequencies, and we employ raytracing calculations to perform its detailed analysis. An isolated density structure responsible for the reflection of the sounding signal back to the spacecraft is assumed, and the relevant ionospheric signal propagation is properly evaluated. We show that initially oblique sounding signals get progressively more oblique during their propagation, imposing an upper threshold on the angular propagation distance between the spacecraft and the reflecting density structure, in line with the observations. Considering realistic propagation paths further allows us to explain the frequency dependence of the observed time delays and to accurately model the entire event. The obtained results are consistent with the spacecraft passing very close to a spatially limited density structure. We also show that the results obtained using realistic raytracing calculations are significantly different from the results obtained using additional simplifying assumptions.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10305 - Fluids and plasma physics (including surface physics)
Result continuities
Project
<a href="/en/project/LTAUSA17070" target="_blank" >LTAUSA17070: Electromagnetic waves in planetary ionospheres and magnetospheres</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2019
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Geophysical Research: Planets
ISSN
2169-9097
e-ISSN
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Volume of the periodical
124
Issue of the periodical within the volume
5
Country of publishing house
US - UNITED STATES
Number of pages
11
Pages from-to
1177-1187
UT code for WoS article
000471600600003
EID of the result in the Scopus database
2-s2.0-85065245074