scholarly journals A New Ionospheric Index to Investigate Electron Temperature Small-Scale Variations in the Topside Ionosphere

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 290
Author(s):  
Alessio Pignalberi ◽  
Igino Coco ◽  
Fabio Giannattasio ◽  
Michael Pezzopane ◽  
Paola De Michelis ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Current Knowledge ◽  
Time Derivative ◽  
European Space Agency ◽  
Rate Of Change ◽  
Small Scale ◽  
Topside Ionosphere ◽  
Langmuir Probes ◽  
Swarm Satellites ◽  
Statistical Trends

The electron temperature (Te) behavior at small scales (both spatial and temporal) in the topside ionosphere is investigated through in situ observations collected by Langmuir Probes on-board the European Space Agency Swarm satellites from the beginning of 2014 to the end of 2020. Te observations are employed to calculate the Rate Of change of electron TEmperature Index (ROTEI), which represents the standard deviation of the Te time derivative calculated over a window of fixed width. As a consequence, ROTEI provides a description of the small-scale variations of Te along the Swarm satellites orbit. The extension of the dataset and the orbital configuration of the Swarm satellites allowed us to perform a statistical analysis of ROTEI to unveil its mean spatial, diurnal, seasonal, and solar activity variations. The main ROTEI statistical trends are presented and discussed in the light of the current knowledge of the phenomena affecting the distribution and dynamics of the ionospheric plasma, which play a key role in triggering Te small-scale variations. The appearance of unexpected high values of ROTEI at mid and low latitudes for specific magnetic local time sectors is revealed and discussed in association with the presence of Te spikes recorded by Swarm satellites under very specific conditions.

scholarly journals On the Electron Temperature in the Topside Ionosphere as Seen by Swarm Satellites, Incoherent Scatter Radars, and the International Reference Ionosphere Model

2021 ◽  
Vol 13 (20) ◽  
pp. 4077
Author(s):  
Alessio Pignalberi ◽  
Fabio Giannattasio ◽  
Vladimir Truhlik ◽  
Igino Coco ◽  
Michael Pezzopane ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Time Window ◽  
European Space Agency ◽  
International Reference Ionosphere ◽  
Topside Ionosphere ◽  
Iri Model ◽  
International Reference ◽  
Incoherent Scatter ◽  
Swarm Satellites ◽  
Incoherent Scatter Radars

The global statistical median behavior of the electron temperature (Te) in the topside ionosphere was investigated through in-situ data collected by Langmuir Probes on-board the European Space Agency Swarm satellites constellation from the beginning of 2014 to the end of 2020. This is the first time that such an analysis, based on such a large time window, has been carried out globally, encompassing more than half a solar cycle, from the activity peak of 2014 to the minimum of 2020. The results show that Swarm data can help in understanding the main features of Te in the topside ionosphere in a way never achieved before. Te data measured by Swarm satellites were also compared to data modeled by the empirical climatological International Reference Ionosphere (IRI) model and data measured by Jicamarca (12.0°S, 76.8°W), Arecibo (18.2°N, 66.4°W), and Millstone Hill (42.6°N, 71.5°W) Incoherent Scatter Radars (ISRs). Moreover, the correction of Swarm Te data recently proposed by Lomidze was applied and evaluated. These analyses were performed for two main reasons: (1) to understand how the IRI model deviates from the measurements; and (2) to test the reliability of the Swarm dataset as a new possible dataset to be included in the underlying empirical dataset layer of the IRI model. The results show that the application of the Lomidze correction improved the agreement with ISR data above all at mid latitudes and during daytime, and it was effective in reducing the mismatch between Swarm and IRI Te values. This suggests that future developments of the IRI Te model should include the Swarm dataset with the Lomidze correction. However, the existence of a quasi-linear relation between measured and modeled Te values was well verified only below about 2200 K, while for higher values it was completely lost. This is an important result that IRI Te model developers should properly consider when using the Swarm dataset.

Climatology of very high ionospheric electron temperature occurrences as observed by Swarm constellation

2021 ◽  
Author(s):  
Igino Coco ◽  
Giuseppe Consolini ◽  
Paola De Michelis ◽  
Fabio Giannattasio ◽  
Michael Pezzopane ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Physical Parameters ◽  
High Electron ◽  
Langmuir Probes ◽  
Swarm Satellites ◽  
High Electron Temperature ◽  
Physical Quantities ◽  
Very High

<p>After more than seven years in orbit, the ESA Swarm satellites have provided an already large statistics of measurements of several important physical parameters of the ionosphere. In particular, electron density and temperature are measured by pairs of Langmuir Probes, and the quality of such data is now considered good enough for many studies, either science cases or climatological characterisations. Concerning specifically the electron temperature, a rather elusive parameter which is quite difficult to correctly characterize “in situ”, and for which the past literature is not so abundant with respect to other ionospheric physical quantities, the overall distributions observed by Swarm are qualitatively consistent with expectations from theory and past observations. However, a non-negligible amount of high and very high electron temperature values is regularly observed, whose distributions and properties are not trivial. In this study we aim at characterizing such features statistically as a function of latitude, local time, and season.</p>

scholarly journals Swarm Langmuir Probes' data quality and future improvements

2021 ◽  
Author(s):  
Filomena Catapano ◽  
Stephan Buchert ◽  
Enkelejda Qamili ◽  
Thomas Nilsson ◽  
Jerome Bouffard ◽  
...  
Keyword(s):  
Data Quality ◽  
Numerical Models ◽  
European Space Agency ◽  
Langmuir Probes ◽  
Plasma Parameters ◽  
Plasma Dynamics ◽  
High Data ◽  
Space Agency ◽  
Swarm Satellites ◽  
The Impact

Abstract. Swarm is ESA's (European Space Agency) first Earth observation constellation mission, which was launched in 2013 to study the geomagnetic field and its temporal evolution. Two Langmuir Probes (LPs) on board of each of the three Swarm satellites provide very accurate measurements of plasma parameters, which contribute to the the study of the ionospheric plasma dynamics. To maintain a high data quality for scientific and operational applications, the Swarm products are continuously monitored and validated via science-oriented diagnostics. This paper presents an overview of the data quality of the Swarm Langmuir Probes' measurements. The data quality is assessed by analysing short and long data segments, where the latter are selected sufficiently long to consider the impact of the solar activity. Langmuir Probes data have been validated through comparison with numerical models, other satellite missions, and ground observations. Based on the outcomes from quality control and validation activities conduced by ESA, as well as scientific analysis and feedback provided by the user community, the Swarm products are regularly upgraded. In this paper we discuss the data quality improvements introduced with the latest baseline, and how the data quality is influenced by the solar cycle. The main anomaly affecting the LP measurements is described, as well as possible improvements to be implemented in future baselines.

scholarly journals Looking for a proxy of the ionospheric turbulence with Swarm data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paola De Michelis ◽  
Giuseppe Consolini ◽  
Alessio Pignalberi ◽  
Roberta Tozzi ◽  
Igino Coco ◽  
...  
Keyword(s):  
Electron Density ◽  
Geomagnetic Activity ◽  
Density Fluctuations ◽  
Rate Of Change ◽  
Topside Ionosphere ◽  
Joint Probability Distribution ◽  
Activity Levels ◽  
Scaling Exponents ◽  
Electron Density Fluctuations ◽  
Scaling Features

AbstractThe present work focuses on the analysis of the scaling features of electron density fluctuations in the mid- and high-latitude topside ionosphere under different conditions of geomagnetic activity. The aim is to understand whether it is possible to identify a proxy that may provide information on the properties of electron density fluctuations and on the possible physical mechanisms at their origin, as for instance, turbulence phenomena. So, we selected about 4 years (April 2014–February 2018) of 1 Hz electron density measurements recorded on-board ESA Swarm A satellite. Using the Auroral Electrojet (AE) index, we identified two different geomagnetic conditions: quiet (AE < 50 nT) and active (AE > 300 nT). For both datasets, we evaluated the first- and second-order scaling exponents and an intermittency coefficient associated with the electron density fluctuations. Then, the joint probability distribution between each of these quantities and the rate of change of electron density index was also evaluated. We identified two families of plasma density fluctuations characterized by different mean values of both the scaling exponents and the considered ionospheric index, suggesting that different mechanisms (instabilities/turbulent processes) can be responsible for the observed scaling features. Furthermore, a clear different localization of the two families in the magnetic latitude—magnetic local time plane is found and its dependence on geomagnetic activity levels is analyzed. These results may well have a bearing about the capability of recognizing the turbulent character of irregularities using a typical ionospheric plasma irregularity index as a proxy.

scholarly journals Effect of the gas puff location on the divertor plasma properties in COMPASS tokamak

2020 ◽  
Vol 1492 (1) ◽  
pp. 012003
Author(s):  
M Dimitrova ◽  
M Tomes ◽  
Tsv Popov ◽  
R Dejarnac ◽  
J Stockel ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Vacuum Chamber ◽  
Plasma Potential ◽  
Saturation Current ◽  
Langmuir Probes ◽  
Plasma Parameters ◽  
Plasma Properties ◽  
Low Field ◽  
Saturation Current Density ◽  
Deuterium Gas

Abstract Langmuir probes are used to study the plasma parameters in the divertor during deuterium gas puff injection on the high- (HFS) or low-field sides (LFS). The probe data were processed to evaluate the plasma potential and the electron temperatures and densities. A difference was found in the plasma parameters depending on the gas puff location. In the case of a gas puff on the LFS, the plasma parameters changed vastly, mainly in the inner divertor – the plasma potential, the ion saturation-current density and the electron temperature dropped. After the gas puff, the electron temperature changed from 10-15 eV down to within the 5-9 eV range. As a result, the parallel heat-flux density decreased. At the same time, in the outer divertor the plasma parameters remained the same. We thus concluded that using a gas puff on the LFS will facilitate reaching a detachment regime by increasing the density of puffed neutrals. When the deuterium gas puff was on the HFS, the plasma parameters in the divertor region remained almost the same before and during the puff. The electron temperature decreased with just few eV as a result of the increased amount of gas in the vacuum chamber.

scholarly journals Ionosphere Influenced From Lower-Lying Atmospheric Regions

2021 ◽  
Vol 8 ◽  
Author(s):  
Petra Koucká Knížová ◽  
Jan Laštovička ◽  
Daniel Kouba ◽  
Zbyšek Mošna ◽  
Katerina Podolská ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Source Region ◽  
Upper Atmosphere ◽  
Lower Atmosphere ◽  
Small Scale ◽  
Atmospheric Waves ◽  
Ionospheric Variability ◽  
Secular Variations ◽  
Wide Scale ◽  
Academy Of Sciences

The ionosphere represents part of the upper atmosphere. Its variability is observed on a wide-scale temporal range from minutes, or even shorter, up to scales of the solar cycle and secular variations of solar energy input. Ionosphere behavior is predominantly determined by solar and geomagnetic forcing. However, the lower-lying atmospheric regions can contribute significantly to the resulting energy budget. The energy transfer between distant atmospheric parts happens due to atmospheric waves that propagate from their source region up to ionospheric heights. Experimental observations show the importance of the involvement of the lower atmosphere in ionospheric variability studies in order to accurately capture small-scale features of the upper atmosphere. In the Part I Coupling, we provide a brief overview of the influence of the lower atmosphere on the ionosphere and summarize the current knowledge. In the Part II Coupling Evidences Within Ionospheric Plasma—Experiments in Midlatitudes, we demonstrate experimental evidence from mid-latitudes, particularly those based on observations by instruments operated by the Institute of Atmospheric Physics, Czech Academy of Sciences. The focus will mainly be on coupling by atmospheric waves.

scholarly journals Excitation of zonal flow by the modulational instability in electron temperature gradient driven turbulence

2008 ◽  
Vol 74 (3) ◽  
pp. 381-389 ◽  
Author(s):  
Yu. A. ZALIZNYAK ◽  
A. I. YAKIMENKO ◽  
V. M. LASHKIN
Keyword(s):  
Temperature Gradient ◽  
Electron Temperature ◽  
Large Scale ◽  
Modulational Instability ◽  
Zonal Flow ◽  
Finite Amplitude ◽  
Small Scale ◽  
Drift Waves ◽  
Zonal Flows ◽  
Electron Temperature Gradient

AbstractThe generation of large-scale zonal flows by small-scale electrostatic drift waves in electron temperature gradient driven turbulence model is considered. The generation mechanism is based on the modulational instability of a finite amplitude monochromatic drift wave. The threshold and growth rate of the instability as well as the optimal spatial scale of zonal flow are obtained.

Monitoring the plasmapause dynamics at LEO

2021 ◽  
Author(s):  
Balázs Heilig ◽  
Claudia Stolle ◽  
Jan Rauberg ◽  
Guram Kervalishvili
Keyword(s):  
Small Scale ◽  
Topside Ionosphere ◽  
Dynamic Coupling ◽  
Ion Drift ◽  
The Past ◽  
Scale Field ◽  
Funded Project ◽  
Mutual Relations ◽  
Langmuir Probe Measurements ◽  
Probe Measurements

&lt;p&gt;In the past decades researchers have revealed links between a series of sub-auroral ionospheric phenomena and the plasmapause (PP) dynamics, such as the mid-latitude ionospheric trough (MIT) and the associated sub-auroral temperature enhancement (SETE), the light-ion trough (LIT), the sub-auroral ion drift (SAID) or the more intense sub-auroral polarisation stream (SAPS), and most recently, the inner boundary of small-scale field-aligned currents (SSFACs). Most of these phenomena can be directly observed by the Swarm constellation of ESA at LEO. Thus, Swarm presents a unique opportunity to study the relations between them and also their relation to the PP dynamics.&lt;/p&gt;&lt;p&gt;In a recent Swarm DISC project, PRISM (Plasmapause Related boundaries in the topside Ionosphere as derived from Swarm Measurements), three new products have been developed. Two products characterise the MIT (and the associated SETE). The MITx_LP utilises the Langmuir probe measurements of electron density and temperature, while the MITxTEC product derives the MIT properties from GPS TEC observations. The third product, PPIxFAC provides information on the location and the main characteristics of the equatorial boundary of SSFACs, and it also includes a proxy for the location of the PP at MLT midnight.&lt;/p&gt;&lt;p&gt;In this presentation we introduce the above Swarm L2 products, present the results of a comparative study aiming at revealing their mutual relations and also their dynamic coupling to the PP. Then we demonstrate how the observations of all these ionospheric phenomena combined can be used to develop an improved proxy for monitoring the PP dynamics at LEO as one of the goals of our new ESA-funded project PLASMA.&lt;/p&gt;

scholarly journals Challenges in uncovering non-invasive biomarkers of endometriosis

2020 ◽  
Vol 245 (5) ◽  
pp. 437-447
Author(s):  
Quanah J Hudson ◽  
Alexandra Perricos ◽  
Rene Wenzl ◽  
Iveta Yotova
Keyword(s):  
High Throughput Screening ◽  
Large Scale ◽  
Biomarker Discovery ◽  
Current Knowledge ◽  
Reproductive Age ◽  
Small Scale ◽  
Common Disease ◽  
Sample Collection ◽  
Childbearing Age ◽  
Cohort Selection

Endometriosis affects up to 10% of women of childbearing age, causing symptoms that can include chronic pelvic pain and reduced fertility. The symptoms are not specific to the disease and can be confused with other gynecological conditions or normal menstruation. Currently, the disease can be only definitively diagnosed by laparoscopy, as no clinically accepted biomarker exists. Biomarker discovery can either follow a hypothesis-driven approach selecting targets to be tested based on current knowledge of the disease, or take an unbiased high-throughput screening “omics” approach, such as transcriptomics or proteomics, to identify markers that are unique or elevated in accessible bodily fluids of patients with the disease. Numerous studies have been conducted using these approaches to try and identify endometriosis biomarkers, but variabilities in study design, cohort selection, and analysis, together with the fact that most studies were small-scale, have made independent validation of biomarker candidates difficult. Therefore, efforts are underway to standardize cohort selection, patient data, and sample collection to allow better cross-study comparisons. Large scale multi-center studies using this standardized approach are necessary to validate existing endometriosis biomarker candidates and uncover potential new markers. Given the complexity and heterogeneity of the disease, it is likely that a panel of biomarkers will be necessary to diagnose and categorize endometriosis. Impact statement Endometriosis is a common disease affecting reproductive age women, which is associated with chronic pain and reduced fertility reducing the quality of life of many women. Definitive diagnosis requires invasive laparoscopic surgery creating a high barrier to diagnosis that can delay the onset of treatment significantly. Clinically approved biomarkers of endometriosis are currently lacking, making the discovery and validation of biomarkers that would lead to earlier diagnosis a priority for improving treatment of the disease.

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