A Sporadic Third Layer in the Ionosphere of Mars

Science ◽  
2005 ◽  
Vol 310 (5749) ◽  
pp. 837-839 ◽  
Author(s):  
M. Pätzold ◽  
S. Tellmann ◽  
B. Häusler ◽  
D. Hinson ◽  
R. Schaa ◽  
...  
Keyword(s):  
Electron Density ◽  
Charge Exchange ◽  
Layer Structure ◽  
Electron Densities ◽  
Ionospheric Layer ◽  
Density Profiles ◽  
Mars Express ◽  
Radio Science ◽  
Martian Ionosphere ◽  
Electron Density Profiles

The daytime martian ionosphere has been observed as a two-layer structure with electron densities that peak at altitudes between about 110 and 130 kilometers. The Mars Express Orbiter Radio Science Experiment on the European Mars Express spacecraft observed, in 10 out of 120 electron density profiles, a third ionospheric layer at altitude ranges of 65 to 110 kilometers, where electron densities, on average, peaked at 0.8 × 1010 per cubic meter. Such a layer has been predicted to be permanent and continuous. Its origin has been attributed to ablation of meteors and charge exchange of magnesium and iron. Our observations imply that this layer is present sporadically and locally.

scholarly journals The processing of electron density profiles from the Mars Express MARSIS topside sounder

Radio Science ◽  
2013 ◽  
Vol 48 (3) ◽  
pp. 197-207 ◽  
Author(s):  
D. D. Morgan ◽  
O. Witasse ◽  
E. Nielsen ◽  
D. A. Gurnett ◽  
F. Duru ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Profiles ◽  
Mars Express ◽  
Electron Density Profiles

Mutual radio occultation experiment between ExoMars Trace Gas Orbiter and Mars Express: algorithms testing

2021 ◽  
Author(s):  
Bruno Nava ◽  
Yenca Migoya-Orue ◽  
Anton Kashcheyev ◽  
Beatriz Sánchez-Cano ◽  
Olivier Witasse ◽  
...  
Keyword(s):  
Experimental Data ◽  
Electron Density ◽  
Doppler Shift ◽  
Radio Occultation ◽  
Trace Gas ◽  
Neutral Atmosphere ◽  
Ionospheric Electron Density ◽  
Density Profiles ◽  
Mars Express ◽  
Electron Density Profiles

<p>Radio Occultation (RO) is a very powerful technique to probe a planetary atmosphere, in providing vertical density profiles of the neutral atmosphere and ionosphere. The standard method uses a radio link between a spacecraft and an Earth ground station. Nevertheless, the possibility to obtain information about the Martian atmosphere with mutual RO events, using data from NASA Mars Odyssey and Mars Reconnaissance Orbiters (MRO), has been demonstrated by Ao et al. (2015).<br />Taking advantage of two European spacecraft in orbit around Mars, the European Space Agency is currently preparing experiments of mutual RO between Mars Express (MEX) and the ExoMars Trace Gas Orbiter (TGO). In preparation of MEX and TGO data inversion and analysis, a simulation-based strategy has been adopted and an algorithm able to retrieve vertical electron density profiles from Doppler shift measurements has been implemented and validated. Subsequently, in order to test the mentioned algorithm with experimental data, the same three RO events considered in the paper by Ao et al. (2015) have been processed. In particular, for each RO event, having the information about the satellites’ orbit, the (excess) Doppler shift values corresponding to the Mars Odyssey-MRO ray-paths have been converted to bending angles as a function of impact parameter. Then, assuming a spherical symmetry (Fjeldbo et al., 1971) for the ionosphere electron density, the bending angles have been transformed (through Abel integral) to a vertical refractivity profile, which, in turn, has been converted to an ionospheric electron density profile.<br />In this work, the results obtained by the application of the mentioned inversion algorithm to experimental data will be presented, with particular focus on the retrieval of the ionospheric electron density profiles.</p> <p><strong>References</strong></p> <p>Ao, C. O., C. D. Edwards Jr., D. S. Kahan, X. Pi, S. W. Asmar, and A. J. Mannucci (2015), A first demonstration of Mars crosslink occultation measurements, Radio Sci., 50, 997–1007, doi:10.1002/2015RS005750.</p> <p>Fjeldbo, G., A. J. Kliore, and V. R. Eshleman (1971), The neutral atmosphere of Venus as studied with the Mariner V radio occultation<br />experiments, Astron. J., 76, 123–140.</p>

scholarly journals Solar wind modulation of the Martian ionosphere observed by Mars Global Surveyor

2004 ◽  
Vol 22 (6) ◽  
pp. 2277-2281 ◽  
Author(s):  
J.-S. Wang ◽  
E. Nielsen
Keyword(s):  
Solar Wind ◽  
Electron Density ◽  
Neutral Atmosphere ◽  
Mars Global Surveyor ◽  
Ionospheric Electron Density ◽  
Density Profiles ◽  
Energetic Proton ◽  
Martian Ionosphere ◽  
Proton Precipitation ◽  
Electron Density Profiles

Abstract. Electron density profiles in the Martian ionosphere observed by the radio occultation experiment on board Mars Global Surveyor have been analyzed to determine if the densities are influenced by the solar wind. Evidence is presented that the altitude of the maximum ionospheric electron density shows a positive correlation to the energetic proton flux in the solar wind. The solar wind modulation of the Martian ionosphere can be attributed to heating of the neutral atmosphere by the solar wind energetic proton precipitation. The modulation is observed to be most prominent at high solar zenith angles. It is argued that this is consistent with the proposed modulation mechanism.

scholarly journals Error analysis of Abel retrieved electron density profiles from radio occultation measurements

2010 ◽  
Vol 28 (1) ◽  
pp. 217-222 ◽  
Author(s):  
X. Yue ◽  
W. S. Schreiner ◽  
J. Lei ◽  
S. V. Sokolovskiy ◽  
C. Rocken ◽  
...  
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Electron Content ◽  
Electron Densities ◽  
Density Profiles ◽  
Total Electron ◽  
The North ◽  
Spring Equinox ◽  
Electron Density Profiles ◽  
Artificial Plasma

Abstract. This letter reports for the first time the simulated error distribution of radio occultation (RO) electron density profiles (EDPs) from the Abel inversion in a systematic way. Occultation events observed by the COSMIC satellites are simulated during the spring equinox of 2008 by calculating the integrated total electron content (TEC) along the COSMIC occultation paths with the "true" electron density from an empirical model. The retrieval errors are computed by comparing the retrieved EDPs with the "true" EDPs. The results show that the retrieved NmF2 and hmF2 are generally in good agreement with the true values, but the reliability of the retrieved electron density degrades in low latitude regions and at low altitudes. Specifically, the Abel retrieval method overestimates electron density to the north and south of the crests of the equatorial ionization anomaly (EIA), and introduces artificial plasma caves underneath the EIA crests. At lower altitudes (E- and F1-regions), it results in three pseudo peaks in daytime electron densities along the magnetic latitude and a pseudo trough in nighttime equatorial electron densities.

scholarly journals Mars Global Surveyor radio science electron density profiles : Neutral atmosphere implications

2001 ◽  
Vol 28 (16) ◽  
pp. 3091-3094 ◽  
Author(s):  
Stephen W. Bougher ◽  
Steffi Engel ◽  
David P. Hinson ◽  
Jeffrey M. Forbes
Keyword(s):  
Electron Density ◽  
Neutral Atmosphere ◽  
Mars Global Surveyor ◽  
Density Profiles ◽  
Radio Science ◽  
Electron Density Profiles

scholarly journals Validation of SSUSI-derived auroral electron densities: comparisons to EISCAT data

2021 ◽  
Vol 39 (5) ◽  
pp. 899-910
Author(s):  
Stefan Bender ◽  
Patrick J. Espy ◽  
Larry J. Paxton
Keyword(s):  
Electron Density ◽  
Electron Energy ◽  
Ionization Rate ◽  
Absolute Difference ◽  
Electron Densities ◽  
Particle Precipitation ◽  
Density Profiles ◽  
Average Electron Energy ◽  
Auroral Electron ◽  
Electron Density Profiles

Abstract. The coupling of the atmosphere to the space environment has become recognized as an important driver of atmospheric chemistry and dynamics. In order to quantify the effects of particle precipitation on the atmosphere, reliable global energy inputs on spatial scales commensurate with particle precipitation variations are required. To that end, we have validated auroral electron densities derived from the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) data products for average electron energy and electron energy flux by comparing them to EISCAT (European Incoherent Scatter Scientific Association) electron density profiles. This comparison shows that SSUSI far-ultraviolet (FUV) observations can be used to provide ionization rate and electron density profiles throughout the auroral region. The SSUSI on board the Defense Meteorological Satellite Program (DMSP) Block 5D3 satellites provide nearly hourly, 3000 km wide high-resolution (10 km×10 km) UV snapshots of auroral emissions. These UV data have been converted to average energies and energy fluxes of precipitating electrons. Here we use those SSUSI-derived energies and fluxes as input to standard parametrizations in order to obtain ionization-rate and electron-density profiles in the E region (90–150 km). These profiles are then compared to EISCAT ground-based electron density measurements. We compare the data from two satellites, DMSP F17 and F18, to the Tromsø UHF radar profiles. We find that differentiating between the magnetic local time (MLT) “morning” (03:00–11:00 MLT) and “evening” (15:00–23:00 MLT) provides the best fit to the ground-based data. The data agree well in the MLT morning sector using a Maxwellian electron spectrum, while in the evening sector using a Gaussian spectrum and accounting for backscattered electrons achieved optimum agreement with EISCAT. Depending on the satellite and MLT period, the median of the differences varies between 0 % and 20 % above 105 km (F17) and ±15 % above 100 km (F18). Because of the large density gradient below those altitudes, the relative differences get larger, albeit without a substantially increasing absolute difference, with virtually no statistically significant differences at the 1σ level.

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