Preliminary validation of in situ electron density measurements onboard CSES using observations from Swarm Satellites

2019 ◽  
Vol 64 (4) ◽  
pp. 982-994 ◽  
Author(s):  
Xiuying Wang ◽  
Wanli Cheng ◽  
Dehe Yang ◽  
Dapeng Liu
Keyword(s):  
Electron Density ◽  
Density Measurements ◽  
Preliminary Validation ◽  
Swarm Satellites

scholarly journals Stratification observed by the in situ plasma density measurements from the Swarm satellites

2020 ◽  
Vol 38 (2) ◽  
pp. 517-526
Author(s):  
Xiuying Wang ◽  
Wanli Cheng ◽  
Zihan Zhou ◽  
Dehe Yang ◽  
Jing Cui ◽  
...  
Keyword(s):  
Plasma Density ◽  
Continuous Distribution ◽  
Direct Analysis ◽  
Density Measurements ◽  
Equatorial Ionization Anomaly ◽  
Swarm Satellites ◽  
Plasma Peak ◽  
First Time ◽  
New Discovery

Abstract. The stratification phenomenon is investigated using the simultaneous in situ plasma density measurements obtained by the Swarm satellites orbiting at different altitudes above the F2 peak. For the first time, the continuous distribution morphology and the exact locations are obtained for the nighttime stratification, which show that the stratification events are centered at the EIA (equatorial ionization anomaly) trough and extend towards the two EIA crests, with the most significant part being located at the EIA trough. Another new discovery is the stratification in southern mid-latitudes; stratification events in this region are located on a local plasma peak sandwiched by two lower density strips covering all the longitudes. The formation mechanism of the stratification for the two latitudinal regions is discussed, but the stratification mechanism in southern mid-latitudes remains an unsolved problem. Highlights. This paper addresses the following: first application of in situ plasma densities for the direct analysis of the stratification in F2 layer, refined features of the exact location and continuous morphology for the stratification phenomenon, a new discovery of stratification covering all longitudes in southern mid-latitudes.

scholarly journals Stratification observed by the in situ measurements from the Swarm satellites

2020 ◽  
Author(s):  
Xiuying Wang ◽  
Wanli Cheng ◽  
Zihan Zhou ◽  
Dehe Yang ◽  
Jing Cui ◽  
...  
Keyword(s):  
Unsolved Problem ◽  
Continuous Distribution ◽  
Density Measurements ◽  
Equatorial Ionization Anomaly ◽  
Swarm Satellites ◽  
Plasma Peak ◽  
First Time ◽  
Different Altitudes ◽  
New Discovery

Abstract. Stratification phenomenon is investigated using the simultaneous in situ plasma density measurements obtained by the Swarm satellites orbiting at different altitudes above F2 peak. For the first time, the continuous distribution morphology and the exact locations are obtained for the nighttime stratification, which show that the stratification events are centered at the EIA (equatorial ionization anomaly) trough and extend towards the two EIA crests with the most significant part being located at the EIA trough. Another new discovery is the stratification in southern mid-latitudes; stratification events in this region are located on a local plasma peak sandwiched by two lower density strips covering all the longitudes. The formation mechanism of the stratification for the two latitudinal regions is discussed, but the stratification mechanism in southern mid-latitudes remains an unsolved problem.

scholarly journals Ionospheric irregularities and scintillations: a direct comparison of in situ density observations with ground-based L-band receivers

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Sharon Aol ◽  
Stephan Buchert ◽  
Edward Jurua
Keyword(s):  
Electron Density ◽  
Satellite Communication ◽  
Density Fluctuations ◽  
Ionospheric Irregularities ◽  
Langmuir Probes ◽  
Amplitude Scintillation ◽  
Swarm Satellites ◽  
L Band ◽  
Electron Density Fluctuations

Abstract Ionospheric irregularities can affect satellite communication and navigation by causing scintillations of radio signals. The scintillations are routinely measured using ground-based networks of receivers. This study presents observations of ionospheric irregularities by Langmuir probes on the Swarm satellites. They are compared with amplitude scintillation events recorded by the Global Positioning System-Scintillation Network and Decision Aid (GPS-SCINDA) receiver installed in Mbarara (Lat: $$0.6^{\circ }\hbox {S}$$ 0 . 6 ∘ S , Lon: $$30.8^{\circ }\hbox {E}$$ 30 . 8 ∘ E , Mag. lat: $$10.2^{\circ }\hbox {S}$$ 10 . 2 ∘ S ). The study covers the years from 2014 to 2018 when both data sets were available. It was found that the ground-based amplitude scintillations were enhanced when Swarm registered ionospheric irregularities for a large number of passes. The number of matching observations was greater for Swarm A and C which orbited at lower altitudes compared to Swarm B. However, some counterexamples, i.e., cases when in situ electron density fluctuations were not associated with any observed L-band amplitude scintillation and vice versa, were also found. Therefore, mismatches between observed irregularity structures and scintillations can occur just over a few minutes and within distances of a few tens of kilometers. The amplitude scintillation strength, characterized by the S4 index was estimated from the electron density data using the well-known phase screen model for weak scattering. The derived amplitude scintillation was on average lower for Swarm B than for A and C and less in accordance with the observed range. Irregularities at an altitude of about 450 km contribute strongly to scintillations in the L-band, while irregularities at about 510-km altitude contribute significantly less. We infer that in situ density fluctuations observed on passes over or near Mbarara may be used to indicate the risk that ionospheric radio wave scintillations occur at that site.

Analysis of Swarm Electric Field Data in View of Tsunami Events and related Earthquakes

2020 ◽  
Author(s):  
Wojciech Jarmolowski ◽  
Pawel Wielgosz ◽  
Anna Krypiak-Gregorczyk ◽  
Beata Milanowska
Keyword(s):  
Electric Field ◽  
Electron Density ◽  
Electron Content ◽  
Langmuir Probes ◽  
Time And Space ◽  
Total Electron ◽  
Swarm Satellites ◽  
High Orbit ◽  
Orbital Height

<p>Three Swarm satellites are equipped with Langmuir Probes (LP) measuring in-situ electron density of Earth electric field and POD GNSS receivers determining topside total electron content (TEC) in the upper ionosphere. It is proved that different events on the Earth and in its atmopshere have their own impact on Earth electric field, and the earthquakes are in this group. Many strong earthquakes induce tsunamis, which are also suspected as contributing to the gravity waves having an impact on the ionospheric TEC. These reasons encourage to the study on the sensitivity of Swarm LP and POD GNSS data to the abovementioned phenomena. Referring to the sensitivity of TEC data derived from GNSS stations to Earthquakes, sensitivity of GNSS and LP data at around 500 km high orbit is analyzed here. A similar orbital height can be found in case of many LEO missions equipped at least with GNSS POD receivers, which makes Swarm especially interesting data acquisition platforms.</p><p>The investigation of Swarm data in view of Tsunamis and earthquakes is difficult due to several factors. There are only three satellites, the two of which fly almost together, which gives in fact only two points of the survey. The orbital repetition period is long, which seriously limits the number of comparable observations in terms of the location and time of the day. Finally, the number of large earthquakes and tsunami events in time of Swarm science mission is low, and many Earthquakes do not coincide sufficiently with Swarm passes in time and space. All these factors, however, doesn’t exclude an opportunity of analyzing of Swarm data passes above the earthquakes of magnitude nearby 8, linked with the tsunamis reaching several decimeters.</p><p>Swarm LP data is detrended and analyzed before the earthquakes and also during the earthquakes and resulting tsunami events. The GNSS POD topside TEC from Swarm is analyzed together as a background for LP data. In-situ electron density disturbances occurring during a pass close to the earthquake is compared to selected STEC measurements between LEO and GNSS satellites. Additionally absolute STEC values from selected nearby ground stations are analyzed in order to  find existing correlations for detected disturbances in the electric and magnetic fields. All the observations are sparse in time and space, and therefore, leave some unanswered questions and uncertainties. However, several interesting perturbations over earthquake/tsunami events are observable in both Swarm LP data and GNSS TEC data.</p>

Theoretical research of electron-density measurements of plane targets using soft XRL deflectometry

2001 ◽  
Vol 11 (PR2) ◽  
pp. Pr2-479-Pr2-481
Author(s):  
C. Ye ◽  
G. Zhang ◽  
T. Zhang ◽  
H. Peng ◽  
W. Zheng
Keyword(s):  
Electron Density ◽  
Theoretical Research ◽  
Density Measurements

Catalytic activity of rhodium(I) complexes containing (ω-trimethylsilylalkyl)diphenylphosphines

1980 ◽  
Vol 45 (8) ◽  
pp. 2219-2223 ◽  
Author(s):  
Marie Jakoubková ◽  
Martin Čapka
Keyword(s):  
Catalytic Activity ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Electron Density ◽  
Phosphorus Atom ◽  
Proton Acceptor ◽  
Trimethylsilyl Group ◽  
Kinetics Of

Kinetics of homogenous hydrogenation of 1-heptene catalysed by rhodium(I) complexes prepared in situ from μ,μ'-dichloro-bis(cyclooctenerhodium) and phosphines of the type RP(C6H5)2 (R = -CH3, -(CH2)nSi(CH3)3; n = 1-4) have been studied. The substitution of the ligands by the trimethylsilyl group was found to increase significantly the catalytic activity of the complexes. The results are discussed in relation to the electron density on the phosphorus atom determined by 31P NMR spectroscopy and to its proton acceptor ability determined by IR spectroscopy.

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