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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 (Aprildoi:10.1038/s41598-021-84985-1 pmid:33731772 fatcat:5tmii5cn2be6tgs3vblxmdr4mi
more »... y 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.
Patrick geomagnetic storm occurred on March 17, 2015 (Pignalberi et al. 2018a, b) . ... The obtained results confirm those shown in Pignalberi et al. (2018a, b) for the St. ...doi:10.1186/s40623-018-0952-z fatcat:tckpxp5plzenrlbw35chhmawgy
The ionospheric plasma density irregularities are known to play a role in the propagation of electromagnetic signals and to be one of the most important sources of disturbance for the Global Navigation Satellite System, being responsible for degradation and, sometimes, interruptions of the signals received by the system. In the equatorial ionospheric F region, these plasma density irregularities, known as plasma bubbles, find the suitable conditions for their development during post-sunsetdoi:10.3390/rs14040918 fatcat:xwggs7nubrfolpxzdkurasrewm
more »... . In recent years, important features of plasma bubbles such as their dependence on latitude, longitude, and solar and geomagnetic activities have been inferred indirectly using their magnetic signatures. Here, we study the scaling properties of both the electron density and the magnetic field inside the plasma bubbles using measurements on board the Swarm A satellite from 1 April 2014 to 31 January 2016. We show that the spectral features of plasma irregularities cannot be directly inferred from their magnetic signatures. A relation more complex than the linear one is necessary to properly describe the role played by the evolution of plasma bubbles with local time and by the development of turbulent phenomena.
 , Pignalberi  , Jin et al.  and Piersanti et al.  . Figure 4 reports the obtained results. ...doi:10.3390/rs13040759 fatcat:gtabmdatenchnpjbsn5ajdqt3y
et al. 2014 Pignalberi et al. , 2015 . ... Bossolasco & Elena 1963; Pignalberi et al. 2014) . ...doi:10.1051/swsc/2015031 fatcat:rp6c44bgvfappfxdn524uknte4
TITIPy is open-source and freely downloadable at https://github.com/pignalberi/TITIPy (accessed on 13 May 2021). ... The TITIPy (Topside Ionosphere Turbulence Indices with Python) Python tool is freely downloadable at https://github.com/pignalberi/ TITIPy (accessed on 3 January 2021). ...doi:10.3390/universe7080290 fatcat:ojol5ovssvfhtmtfc2aoo5llti
Preliminary Swarm Langmuir probe measurements recorded during March 2015, a period of time including the St. Patrick storm, are considered. Specifically, six time periods are identified: two quiet periods before the onset of the storm, two periods including the main phase of the storm, and two periods during the recovery phase of the storm. Swarm electron density values are then compared with the corresponding output given by the International Reference Ionosphere (IRI) model, according to itsdoi:10.1186/s40623-016-0466-5 fatcat:pqg44db56reudgvaekbyrxgrba
more »... hree different options for modelling the topside ionosphere. Since the Swarm electron density measurements are still undergoing a thorough validation, a comparison with IRI in terms of absolute values would have not been appropriate. Hence, the similarity of trends embedded in the Swarm and IRI time series is investigated in terms of Pearson correlation coefficient. The analysis shows that the electron density representations made by Swarm and IRI are different for both quiet and disturbed periods, independently of the chosen topside model option. Main differences between trends modelled by IRI and those observed by Swarm emerge, especially at equatorial latitudes, and at northern high latitudes, during the main and recovery phases of the storm. Moreover, very low values of electron density, even lower than 2 × 10 4 cm −3 , were simultaneously recorded in the evening sector by Swarm satellites at equatorial latitudes during quiet periods, and at magnetic latitudes of about ±60° during disturbed periods. The obtained results are an example of the capability of Swarm data to generate an additional valuable dataset to properly model the topside ionosphere.
For a detailed description of the methodology refer to Pignalberi et al. ... (8) ) what is important is the ratio between z and H Epstein , and this ratio behaves well for z → 0 (as showed by Pignalberi et al. 13 ). ...doi:10.1038/s41598-020-73886-4 pmid:33067512 fatcat:vzncmnq7ojejhaddf5kfiqp4uu
Recently, Pignalberi et al. ... this time range, a total of 3,626,729 COSMIC electron density profiles were available, and the most reliable ones were selected by applying the filtering procedure described in the "Methods" section of Pignalberi ...doi:10.3390/atmos12081003 fatcat:mhfrw7mnxrbgzkfzhdwmjedl4e
The storm onset on 7 September 2017, triggered several variations in the ionospheric electron density, causing severe phase fluctuations at polar latitudes in both hemispheres. In addition, although quite rare at high latitudes, clear amplitude scintillations were recorded by two Global Navigation Satellite System receivers during the main phase of the storm. This work attempted to investigate the physical mechanisms triggering the observed amplitude scintillations, with the aim of identifyingdoi:10.3390/rs13132493 fatcat:f47dsb4c4jcerjs6wwz3bgm3me
more »... he conditions favoring such events. We investigated the ionospheric background and other conditions that prevailed when the irregularities formed and moved, following a multi-observations approach. Specifically, we combined information from scintillation parameters and recorded by multi-constellation (GPS, GLONASS and Galileo) receivers located at Concordia station (75.10°S, 123.35°E) and SANAE IV base (71.67°S, 2.84°W), with measurements acquired by the Special Sensor Ultraviolet Spectrographic Imager on board the Defense Meteorological Satellite Program satellites, the Super Dual Auroral Radar Network, the Swarm constellation and ground-based magnetometers. Besides confirming the high degree of complexity of the ionospheric dynamics, our multi-instrument observation identified the physical conditions that likely favor the occurrence of amplitude scintillations at high latitudes. Results suggest that the necessary conditions for the observation of this type of scintillation in high-latitude regions are high levels of ionization and a strong variability of plasma dynamics. Both of these conditions are typically featured during high solar activity.
Values of bTEC at the same locations were calculated through the IRI UP method proposed by Pignalberi et al. (2018a, b) . ... In detail, the International Reference Ionosphere UPdate (IRI UP) procedure, which has been recently developed by Pignalberi et al. (2018a, b) , is used to get, at the same GPS receiver locations, an ...doi:10.1186/s40623-019-1056-0 pmid:31402843 pmcid:PMC6647577 fatcat:hfbiuiefefdoffx3hlwopboimu
., 2016; Pignalberi et al., 2016) , where vTEC measurements highlighted many losses of lock (figures not shown). ...doi:10.5194/angeo-38-703-2020 fatcat:r5b5yxqh7vcxffco4jwxg5ssya
RODI RODI values  can be obtained according to the procedure recently proposed by Pignalberi  through his TITIPy (Topside Ionosphere Turbulence Indices with Python) tool. ... In Pignalberi  , sTEC and corresponding ROTI values are associated with the Ionospheric Pierce Point (IPP), that is, the point where the link path between GPS and Swarm satellites pierces the spherical ...doi:10.3390/rs13112209 fatcat:2usygxtdd5b67d7wjzlxjis25a
A similar dataset referring to T i , for Millstone Hill was recently employed in Pignalberi et al.  . ... For a detailed mathematical description of the Booker profile function formalism, refer to the Appendix section of Pignalberi et al.  . ...doi:10.3390/rs13204077 fatcat:7zcern7xfje23f4errm645keia
Recently, Pezzopane and Pignalberi  proposed an improvement to the topside representation of the NeQuick model This work is licensed under a Creative Commons Attribution 4.0 License. ... Alessio Pignalberi received the B.S. and M.S. degrees in physics from the "Sapienza" University of Rome, Rome, Italy, in 2011 and 2014, respectively, and the Ph.D. degree in geophysics from the "Alma Mater ...doi:10.1109/jstars.2020.2986683 fatcat:s2p6nzuo6femzfnzmws6ve4hee
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