scholarly journals Ionospheric plasma irregularities studied with Swarm satellites

2018 ◽  
Vol 62 ◽  
pp. 01009
Author(s):  
Wojciech J. Miloch ◽  
Yaqi Jin ◽  
Chao Xiong ◽  
Guram Kervalishvili ◽  
Andres Spicher ◽  
...  
Keyword(s):  
Ionospheric Plasma ◽  
Ionospheric Irregularities ◽  
Global Studies ◽  
Gps Receiver ◽  
Magnetic Field Data ◽  
Plasma Irregularities ◽  
Swarm Satellites ◽  
The Magnetic Field ◽  
Level 2

To study and characterise the ionospheric plasma irregularities at all latitudes, one can employ in-situ measurements by satellites in polar orbits, such as the European Space Agency’s Swarm mission. Based on the Swarm data, we have developed the Ionospheric Plasma IRregularities (IPIR) product for a global characterisation of ionospheric irregularities along the satellite track at all latitudes. This new Level-2 data product combines complementary datasets from the Swarm satellites: the electron density from the electric field instrument, the GPS data from the onboard GPS receiver, and the magnetic field data from the onboard magnetometers. This can be used as a new tool for global studies of ionospheric irregularities and turbulence.

scholarly journals Ionospheric Plasma Irregularities Based on In Situ Measurements From the Swarm Satellites

2020 ◽  
Vol 125 (7) ◽  
Author(s):  
Yaqi Jin ◽  
Chao Xiong ◽  
Lasse Clausen ◽  
Andres Spicher ◽  
Daria Kotova ◽  
...  
Keyword(s):  
Ionospheric Plasma ◽  
In Situ Measurements ◽  
Plasma Irregularities ◽  
Swarm Satellites

scholarly journals Climatology of GPS signal loss observed by Swarm satellites

2018 ◽  
Vol 36 (2) ◽  
pp. 679-693 ◽  
Author(s):  
Chao Xiong ◽  
Claudia Stolle ◽  
Jaeheung Park
Keyword(s):  
High Latitude ◽  
Ionospheric Plasma ◽  
Ionospheric Irregularities ◽  
Signal Loss ◽  
Radio Science ◽  
Plasma Irregularities ◽  
Gps Satellites ◽  
Swarm Satellites ◽  
Low Latitudes ◽  
December Solstice

Abstract. By using 3-year global positioning system (GPS) measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20∘ magnetic latitude (MLAT) and high latitudes above 60∘ MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20∘, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver. Keywords. Ionosphere (equatorial ionosphere; ionospheric irregularities) – radio science (radio wave propagation)

scholarly journals Principal Component Gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Principal Component ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Service Oriented ◽  
Sensor Configuration ◽  
Time Required ◽  
First Time ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using space borne instruments requires either a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and time required to build a spacecraft. Here we present an alternative sensor configuration and an algorithm allowing for ulterior removal of the spacecraft generated disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness program and allowing for shorter boom length. The proposed algorithm is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) onboard the Korean geostationary satellite GeoKompsat-2A (GK2A) which uses for the first time a multi-sensor configuration for onboard data cleaning. The successful elimination of disturbances originating from several sources validates the proposed cleaning technique.

Diffusion spreading of middle-latitude ionospheric plasma irregularities

1995 ◽  
Vol 13 (6) ◽  
pp. 617-626 ◽  
Author(s):  
N. Blaunstein
Keyword(s):  
Ionospheric Plasma ◽  
Three Dimensional ◽  
Middle Latitude ◽  
Approximate Model ◽  
Ionospheric Irregularities ◽  
Radio Waves ◽  
Plasma Irregularities ◽  
Relaxation Effects ◽  
Artificial Heating ◽  
Actual Height

Abstract. In contrast to the way that the spreading of irregularities in a plasma is usually considered, the diffusion spreading of irregularities stretched along the geomagnetic field B is examined using a three-dimensional rigorous numerical model of quasi-neutral diffusion in the presence of a magnetic field, in conjunction with the actual height variations of the diffusion and conductivity tensors in the ionosphere. A comparison with the earlier constructed approximate model of unipolar diffusion was made. As in the previous case, the same peculiarities of irregularity spreading in the inhomogeneous background ionospheric plasma were observed. The accuracy of the approximate model for describing the process of spreading of anisotropic ionospheric irregularities is established. Time relaxation effects of real heating-induced ionospheric irregularities on their scale transverse to B are presented using the approximate analytical model for the case of a quasi-homogeneous ionospheric plasma. The calculated results have a vivid physical meaning and can be directly compared with experimental data on the radiophysical observations of artificial heating-induced irregularities created by powerful radio waves in the ionosphere.

scholarly journals Mapping and Survey of Plasma Bubbles over Brazilian Territory

2006 ◽  
Vol 60 (1) ◽  
pp. 69-81 ◽  
Author(s):  
L. F. C. de Rezende ◽  
E. R. de Paula ◽  
I. J. Kantor ◽  
P. M. Kintner
Keyword(s):  
Ionospheric Plasma ◽  
Signal Amplitude ◽  
Gps Receiver ◽  
Tropical Regions ◽  
Plasma Irregularities ◽  
Plasma Bubbles ◽  
Receiver Array ◽  
Field Lines ◽  
Using Data ◽  
The Impact

Ionospheric plasma irregularities or bubbles, that are regions with depleted density, are generated at the magnetic equator after sunset due to plasma instabilities, and as they move upward they map along the magnetic field lines to low latitudes. To analyse the temporal and spatial evolution of the bubbles over Brazilian territory, the mapping of ionospheric plasma bubbles for the night of 17/18 March 2002 was generated using data collected from one GPS receiver array, and applying interpolation techniques. The impact on the performance of Global Navigation Satellites System (GNSS) and on the Space Based Augmentation System (SBAS) in the tropical regions of the GPS signal losses of lock and of the signal amplitude fades during ionospheric irregularities is presented.

scholarly journals Maximum-variance gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Vol 9 (2) ◽  
pp. 451-469
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Maximum Variance ◽  
Service Oriented ◽  
Corrected Data ◽  
Sensor Configuration ◽  
Time Required ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using spaceborne instruments requires a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and the time required to build a spacecraft. Here we present an alternative sensor configuration and a technique allowing for removal of the spacecraft-generated AC disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness programme and allowing for shorter boom length. The final expression of the corrected data takes the form of a linear combination of the measurements from all sensors, allowing for simple onboard software implementation. The proposed technique is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) on board the Korean geostationary satellite GeoKompsat-2A (GK2A). In contrast to other missions where multi-sensor measurements were used to clean the data on the ground, the SOSMAG instrument performs the cleaning on board and transmits the corrected data in real time, as needed by space weather applications. The successful elimination of the AC disturbances originating from several sources validates the proposed cleaning technique.

scholarly journals Structural characterization of the equatorial F region plasma irregularities in the multifractal context

2019 ◽  
Author(s):  
Neelakshi Joshi ◽  
Reinaldo R. Rosa ◽  
Siomel Savio ◽  
Esfhan Alam Kherani ◽  
Francisco Carlos de Meneses ◽  
...  
Keyword(s):  
Ionospheric Plasma ◽  
Fluctuation Analysis ◽  
Multifractal Detrended Fluctuation Analysis ◽  
Plasma Irregularities ◽  
In Situ Data ◽  
F Region ◽  
Linear Algorithms ◽  
Multiplicative Cascade

Abstract. In the emerging ionosphere-space-weather paradigm, investigating dynamical properties of ionospheric plasma irregularities using advanced computational non-linear algorithms is providing new insights into their turbulent-like nature, for instance, the evidence of energy distribution via multiplicative cascade. In this study, we present multifractal analysis of the equatorial F region in situ data obtained from two different experiments performed at Alcântara (2.4° S; 44.4° W), Brazil to explore their scaling structures. First experiment observed several large-medium scale plasma bubbles whereas second experiment observed vertical uplift of the base of F region. Multifractal detrended fluctuation analysis and p-model fit is used to analyze the plasma density fluctuation time series. Result shows presence of multifractality with degree of multifractality 0.53–1.1 with 0.29 ≤ p ≤ 0.4 cascading probability for first experiment. Another experimental data also exhibits multifractality with degree of multifractality 0.27–0.33 with 0.42 ≤ p ≤ 0.44 cascading probability in the ionospheric plasma irregularities. Our results confirm the nonhomogeneous nature of plasma irregularities and characterize the underlying nonhomogeneous multiplicative cascade hypothesis in the ionospheric medium. Differences in terms of scaling and complexity in data belonging to different types of phenomena are also addressed.

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.

Ionospheric plasma irregularities inside the mid-latitude trough by using Swarm observations

2021 ◽  
Author(s):  
Yiwen Liu ◽  
Chao Xiong ◽  
Xin Wan
Keyword(s):  
Ionospheric Plasma ◽  
Density Fluctuations ◽  
Small Scale ◽  
Topside Ionosphere ◽  
Density Measurements ◽  
Plasma Irregularities ◽  
Electron Density And Temperature ◽  
Swarm Satellite ◽  
First Time

<p>The mid-latitude ionospheric trough (MIT) is a well-known feature in the topside ionosphere and plasmasphere. In this report, we investigated the plasma irregularities inside the MIT region based on the high-resolution (2 Hz) measurements of electron density and temperature from the Swarm satellite. We developed a method to automatically identify the mid-latitude trough from Swarm in-situ density measurements, and the small-scale irregularities inside MIT region can also be well determined by considering appropriate thresholds of both the relative (∆Ne/Ne) and absolute (∆Ne) density fluctuations. Further statistics has been performed based-on the multi-years database of identified MITs and irregularities from Swarm. Finally, we provided for the first time the seasonal and magnetic local time distributions of irregularities within the MIT region, and the involved plasma instabilities that cause the irregularities at the MIT region have been discussed.</p>

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