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  • 1
    Publication Date: 2020-10-02
    Description: Il lavoro presenta uno studio preliminare delle fluttuazioni del campo geomagnetico registrate a terra presso 50 osservatori magnetici dislocatiin tutto l’emisfero borealenel corso della tempesta di San Patriziodel marzo 2015. L’applicazione del metodo “Empirical Mode Decomposition”, che ben si adatta all’analisi di segnali frutto di processi non lineari e non stazionari,permette la separazione delle fluttuazioni su diversa scala temporale (breve, 〈200 min,e lunga, 〉200 min). Il differente contributo al segnale sorgente delle fluttuazioni brevi e lunghe, associate a diversi processi magnetosferici, è analizzato in funzione della latitudine nel corso della tempesta geomagnetica.
    Description: Unpublished
    Description: GSSI, L'Aquila
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Keywords: Solar terrestrial relationship
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 2
    Publication Date: 2021-05-31
    Description: Field-aligned currents (FACs) flowing in the auroral ionosphere are a complex system of upward and downward currents, which play a fundamental role in the magnetosphere–ionosphere coupling and in the ionospheric heating. Here, using data from the ESA-Swarm multi-satellite mission, we studied the complex structure of FACs by investigating sign-singularity scaling features for two different conditions of a high-latitude substorm activity level as monitored by the AE index. The results clearly showed the sign-singular character of FACs supporting the complex and filamentary nature of these currents. Furthermore, we found evidence of the occurrence of a topological change of these current systems, which was accompanied by a change of the scaling features at spatial scales larger than 30 km. This change was interpreted in terms of a sort of symmetry-breaking phenomenon due to a dynamical topological transition of the FAC structure as a consequence of FACs and substorm current wedge intensification during substorms.
    Description: Italian PNRA under Contract PNRA18 00289-A “Space weather in Polar Ionosphere: the Role of Turbulence”.
    Description: Published
    Description: 708
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
    Keywords: Field-aligned currents ; Ionosphere ; fractals ; Complexty
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2020-10-02
    Description: We present a preliminary study of the properties of the magnetic field’s fluctuations during the St. Patrick’s Day geomagnetic storm occurred on 17 March 2015. We analyse the minute values of the geomagnetic field recorded simultaneously by a latitudinal network of 18 geomagnetic observatories located at different latitudes, from the equatorial regions to the northern high-latitude ones. We apply the Empirical Mode Decomposition (EMD) method to the X (North) and Y (East) components of the geomagnetic field recorded during a period (13 - 30 March 2015) covering the whole duration of the storm. This adaptive method, which can be applied to signals originating from nonlinear and non-stationary processes, permits us to separate fast (𝜏〈200 min) and slow (𝜏〉200 min) magnetic fluctuations, which are related to different magnetospheric processes. Indeed, it has been shown that whilemagneticfluctuationsat long timescales (𝜏〉200 min) showa large degree of correlationbetween solar windparameters and magnetosphericdynamicsproxies, at short timescales(𝜏〈200 min)theyareessentially related to internal magnetospheric processes andseem to be notdirectlydriven by interplanetarychanges. The differentenergycontribution of the fast and slow fluctuationsisinvestigatedas a function of latitudeduring the development of theselectedgeomagneticstorm.The weight of the signal related to the fluctuations on a short time scale shows a dependence on the latitude and geomagnetic activity level.
    Description: Unpublished
    Description: Vienna, Austria
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Keywords: Solar terrestrial relationship
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 4
    Publication Date: 2020-10-02
    Description: We analyze minute values of ground-based geomagnetic fluctuations at about 50 observatories located at throughout the Northern Hemisphere during the St. Patrick's storm in March 2015. The application of the "Empirical Mode Decomposition" method, which is well suitable for the analysis of signals resulting from non-linear and non-stationary processes, it allows the separation of fluctuations on different time scales (short 〈 200 min, and long 〉 200 min). The different contribution to the source signal of short and long fluctuations, associated with different magnetospheric processes, is analyzed as a function of latitude during the geomagnetic storm. The weight of the signal related to the fluctuations on a short time scale shows a dependence on the latitude and geomagnetic activity level.
    Description: Published
    Description: Liegi, Belgio
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Keywords: Solar terrestrial relationship
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
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  • 5
    Publication Date: 2020-10-02
    Description: We analyze the properties of the geomagnetic field fluctuations during a period (13-30 March 2015) characterized by different geomagnetic activity levels including the strongest geomagnetic storm of XXIV solar cycle occurred on 17 March 2015. The one minute values of theX and Y componentsof the geomagnetic field recorded simultaneously in the Northern and Southern hemispheres are analyzed. The Empirical Mode Decomposition (EMD) method is applied to the selected dataset in order to separate short timescale (𝜏〈200 min) and long timescale(𝜏〉200 min) magnetic field fluctuations, which have been suggested to be related to different physical processes. It has been shown that while magnetic fluctuations at long timescales (𝜏〉200 min) show a large degree of correlation between solar wind parameters and magnetospheric dynamics proxies, at short timescales (𝜏〈200 min) they are essentially related to internal magnetospheric processes and seem to be not directly driven by interplanetary changes. Daily maps of the fast and slow magnetic field fluctuations during the selected period are analyzed to investigate the contributionsto the recorded magnetic signal related to the different magnetospheric processes and their dependence on the geomagnetic activity level. A comparison between the two hemispheres isalso shown.
    Description: Published
    Description: San Francisco
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Keywords: Solar terrestrial relationship
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Poster session
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  • 6
    Publication Date: 2024-01-08
    Description: The study investigates the influence of interplanetary magnetic field (IMF) orientation on loss of lock (LoL) events in GPS signals. We analyzed LoLs recorded on two Swarm satellites between July 2014 and December 2021, examining how the signs of the IMF $B_x$, $B_y$, and $B_z$ components affect the distribution of events at high latitudes. Our results reveal an asymmetric distribution of LoL events over 75° magnetic latitude. In the Northern hemisphere, more events occur in the post-noon sector with negative IMF $B_y$, and in the pre-noon sector with positive IMF $B_y$. Conversely, in the Southern hemisphere, pre-noon events increase with negative IMF $B_y$, while post-noon events increase with positive IMF $B_y$. At lower latitudes (50°-75°), IMF $B_y$ does not significantly affect the event distribution, which mainly concentrates in the night sector for both hemispheres. Additionally, we found a connection between IMF $B_y$ and $B_x$, primarily due to the IMF spiral structure. Finally, we discuss our findings in the context of the SuperDARN data-driven model of ionospheric convection patterns, which shows that LoL events frequently cluster in the cusp region, as well as the area where the two convection cells separate.
    Description: Published
    Description: e2023JA031411
    Description: OSA3: Climatologia e meteorologia spaziale
    Description: JCR Journal
    Keywords: GPS Loss of Lock ; Interplanetary Magnetic Field ; Ionosphere ; Swarm satellites ; 01.02. Ionosphere
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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