The lower dayside ionosphere of Mars in light of MEX MaRS radio science observations

2020 ◽  
Author(s):  
Kerstin Peter ◽  
Martin Pätzold ◽  
Gregorio Molina-Cuberos ◽  
Francisco González-Galindo ◽  
Olivier Witasse ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Electron Density ◽  
Impact Ionization ◽  
Extreme Ultraviolet ◽  
Main Peak ◽  
X Rays ◽  
Mars Atmosphere ◽  
Mars Express ◽  
Radio Science ◽  
The Individual

<p>   <img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gepj.a4004f2be2fe53228792951/sdaolpUECMynit/0202CSPE&app=m&a=0&c=0c4e6952561399e83d88c4d43fe544f2&ct=x&pn=gepj.elif" alt="">      <img src="https://contentmanager.copernicus.org/fileStorageProxy.php?f=gepj.7660ec3be2fe56328792951/sdaolpUECMynit/0202CSPE&app=m&a=0&c=0b6ac6aff35b94d80887605627a854c0&ct=x&pn=gepj.elif" alt=""></p><p><strong>Figure 1: MEX-MaRS X-band observations of the dayside ionosphere of Mars for (a) Day of Year (DoY) 343 (2005) and (b) DoY 215 (2014).  Combined X- and S-band (differential Doppler) observations for (c) DoY 011 (2014) and (d) DoY 006 (2006). The gray dashed line indicates the noise level, while the black dashed line marks the lowest valid altitude of the individual observation (details about the parameter derivation in [2]).</strong></p><p>The Mars Express Radio Science experiment (MaRS) on board the Mars Express spacecraft has observed the Mars atmosphere and ionosphere since 2004. More than 900 high-resolution MaRS height profiles of the ionospheric electron density from the topside down to the ionospheric base are available.</p><p>The two dominant features of the undisturbed Martian dayside ionosphere are the main peak (M2), caused mainly by solar radiation in the Extreme Ultraviolet, and the secondary layer (M1), mostly formed by primary and secondary impact ionization of short solar X-rays < 10 nm [1]. The region below the M1 peak is highly variable and regularly contains merged excess electron density regions (Mm) in various shapes [2] (Figures 1).</p><p>More than 15 years of MaRS radio science observations are used to study the behavior of the lowest region of the Martian dayside ionosphere. Categories for the identified Mm shapes are defined and statistics of the individual Mm shape occurrences are provided. The 1-D photochemical model IonA-2 (Ionization in Atmospheres 2 [2]) is applied to investigate which of the identified Mm shapes can be reproduced by solar radiation of the quiet Sun and under solar M- and X-flare conditions.</p><p> </p><p>References</p><p>  [1] Fox J. L. et al. (1996), Adv. Space Res., 17, 11, 203-218.</p><p>  [2] Peter K. (2018), PhD Dissertation, https://kups.ub.uni-koeln.de/8110/.</p>

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.

The influence of crustal magnetic fields on the Martian bow shock : a statistical analysis of Mars Volatile EvolutioN and Mars Express observations

2020 ◽  
Author(s):  
Philippe Garnier ◽  
Christian Jacquey ◽  
Christian Mazelle ◽  
Xiaohua Fang ◽  
Jacob Gruesbeck ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Extreme Ultraviolet ◽  
Dynamic Pressure ◽  
Bow Shock ◽  
Machine Learning Techniques ◽  
Mars Atmosphere ◽  
Mars Express ◽  
Shock Location ◽  
The Impact

<p>The Martian interaction with the solar wind is unique due to the influence of remanent crustal magnetic fields. The recent studies by the Mars Express and Mars Atmosphere and Volatile Evolution missions underline the strong and complex influence of the crustal magnetic fields on the Martian environment and its interaction with the solar wind. Among them is the influence on the dynamic plasma boundaries that shape this interaction and on the bow shock in particular.</p> <p>Compared to other drivers of the shock location (e.g. solar dynamic pressure, extreme ultraviolet fluxes), the influence of crustal magnetic fields are less understood, with essentially differences observed between the southern and northern hemispheres attributed to the crustal fields. In this presentation we analyze in detail the influence of the crustal fields on the Martian shock location by combining for the first time datasets from two different spacecraft (MAVEN/MEX). An application of machine learning techniques will also be used to increase the list of MAVEN shocks published to date. We show in particular the importance for analyzing biases due to multiple parameters of influence through a partial correlation approach. We also compare the impact of crustal fields with the other parameters of influence, and show that the main drivers of the shock location are by order of importance extreme ultraviolet fluxes and magnetosonic Mach number, crustal fields and then solar wind dynamic pressure.</p>

Martian Ionospheric Observation and Modelling

2020 ◽  
Author(s):  
Francisco González-Galindo
Keyword(s):  
Solar Radiation ◽  
Computational Models ◽  
Impact Ionization ◽  
Ionization Rate ◽  
Dust Storms ◽  
Atmospheric Composition ◽  
Topside Ionosphere ◽  
Neutral Atmosphere ◽  
X Rays ◽  
Martian Ionosphere

The Martian ionosphere is a plasma embedded within the neutral upper atmosphere of the planet. Its main source is the ionization of the CO2-dominated Martian mesosphere and thermosphere by energetic EUV solar radiation. The ionosphere of Mars is subject to an important variability induced by changes in its forcing mechanisms (e.g., the UV solar flux) and by variations in the neutral atmosphere (e.g., the presence of global dust storms, atmospheric waves and tides, changes in atmospheric composition, etc.). Its vertical structure is dominated by a maximum in electron concentration at altitude about 120–140 km, coincident with the peak of the ionization rate. Below, there is a secondary peak produced by solar X-rays and photoelectron-impact ionization. A sporadic third layer, possibly of meteoric origin, has been also detected below. The most abundant ion in the Martian ionosphere is O2 +, although O+ can become more abundant in the upper ionospheric layers. While below about 180–200 km the Martian ionosphere is dominated by photochemical processes, above those altitudes the dynamics of the plasma becomes more important. The ionosphere is also an important source of escaping particles via processes such as dissociative recombination of ions or ion pickup. So, characterization of the ionosphere provides or can provide information about such disparate systems and processes as solar radiation reaching the planet, the neutral atmosphere, meteoric influx, atmospheric escape to space, or the interaction of the planet with the solar wind. It is thus not surprising that the interest about this region dates from the beginning of the space era. From the first measurements provided by the Mariner 4 mission in the 1960s to observations by the Mars Express and MAVEN orbiters in the 2010s, our knowledge of this atmospheric region is the consequence of the accumulation of more than 50 years of discontinuous measurements by different space missions. Numerical simulations by computational models able to simulate the processes that shape the ionosphere have also been commonly employed to obtain information about this region, to provide an interpretation of the observations and to fill their gaps. As a result, at the end of the 2010s the Martian ionosphere was the best known one after that of the Earth. However, there are still areas for which our knowledge is far from being complete. Examples are the details and balance of the mechanisms populating the nightside ionosphere, the origin and variability of the lower ionospheric peak, and the precise mechanisms shaping the topside ionosphere.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

scholarly journals Physical and chemical imaging of adhesive interfaces with soft X-rays

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Hiroyuki Yamane ◽  
Masaki Oura ◽  
Osamu Takahashi ◽  
Tomoko Ishihara ◽  
Noriko Yamazaki ◽  
...  
Keyword(s):  
Molecular Level ◽  
Covalent Bond ◽  
Chemical Imaging ◽  
Diglycidyl Ether ◽  
X Rays ◽  
X Ray ◽  
Covalent Bond Formation ◽  
Chemical States ◽  
The Individual ◽  
Physical And Chemical

AbstractAdhesion is an interfacial phenomenon that is critical for assembling carbon structural composites for next-generation aircraft and automobiles. However, there is limited understanding of adhesion on the molecular level because of the difficulty in revealing the individual bonding factors. Here, using soft X-ray spectromicroscopy we show the physical and chemical states of an adhesive interface composed of a thermosetting polymer of 4,4’-diaminodiphenylsulfone-cured bisphenol A diglycidyl ether adhered to a thermoplastic polymer of plasma-treated polyetheretherketone. We observe multiscale phenomena in the adhesion mechanisms, including sub-mm complex interface structure, sub-μm distribution of the functional groups, and molecular-level covalent-bond formation. These results provide a benchmark for further research to examine how physical and chemical states correlate with adhesion, and demonstrate that soft X-ray imaging is a promising approach for visualizing the physical and chemical states at adhesive interfaces from the sub-mm level to the molecular level.

An Improved Collimator for Extreme Ultraviolet and X Rays

1969 ◽  
Vol 40 (7) ◽  
pp. 894-896 ◽  
Author(s):  
J. H. Underwood
Keyword(s):  
Extreme Ultraviolet ◽  
X Rays

scholarly journals Measurements of the effective electron density in an electron beam ion trap using extreme ultraviolet spectra and optical imaging

2018 ◽  
Vol 89 (10) ◽  
pp. 10E119 ◽  
Author(s):  
T. P. Arthanayaka ◽  
P. Beiersdorfer ◽  
G. V. Brown ◽  
M. Hahn ◽  
N. Hell ◽  
...  
Keyword(s):  
Electron Beam ◽  
Optical Imaging ◽  
Electron Density ◽  
Ion Trap ◽  
Extreme Ultraviolet ◽  
Effective Electron ◽  
Ultraviolet Spectra ◽  
Electron Beam Ion Trap
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