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Consolini, Giuseppe
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Consolini, Giuseppe
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Consolini, G.
ORCID
103 results
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- PublicationOpen AccessTime intermittency and spectral features of the geomagnetic field(2004)
; ; ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Consolini, G.; Istituto di Fisica dello Spazio Interplanetario - CNR, Roma, Italy; In the field of geomagnetism a number of studies have been devoted to the investigation of turbulence and intermittency in the outer core fluid motions. Here, in order to obtain information on such phenomena we study the time spectral and self-similarity features of the main geomagnetic field fluctuations as measured on the Earth’s surface. The existence of a power law spectrum, characterised by an exponent a˜-11/3, and an anomalous scaling of q-th order structure functions on time scales longer than 5 years, suggests the occurrence of intermittent turbulence rather than classical Kolmogorov turbulence in the fluid core motions. These results are briefly discussed in connection with the existence of a strong magnetic field and drift-wave turbulence.189 189 - PublicationOpen AccessSwarm‐Derived Indices of Geomagnetic Activity(2021-11)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;Ground-based indices, such as the Dst, ap and AE, have been used for decades to describe the interplay of the terrestrial magnetosphere with the solar wind and provide quanti able indications of the state of geomagnetic activity in general. These indices have been traditionally derived from ground-based observations from magnetometer stations all around the Earth. In the last 7 years though, the highly successful satellite mission Swarm has provided the scienti c community with an abundance of high quality magnetic measurements at Low Earth Orbit (LEO), which can be used to produce the space-based counterparts of these indices, such the Swarm-Dst, Swarm-ap and Swarm-AE indices. In this work, we present the first results from this endeavour, with comparisons against traditionally used parameters. We postulate on the possible usefulness of these Swarm-based products for a more accurate monitoring of the dynamics of the magnetosphere and thus, for providing a better diagnosis of space weather conditions.211 57 - PublicationOpen AccessPrincipal components’ features of mid-latitude geomagnetic daily variation(2010)
; ; ; ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Tozzi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Consolini, G.; INAF-Istituto di Fisica dello Spazio Interplanetario, Roma, Italia; ; The ionospheric and magnetospheric current systems are responsible of the daily magnetic field changes. Recently, the Natural Orthogonal Components (NOC) technique has been applied to model the physical system responsible of the daily variation of the geomagnetic field, efficiently and accurately (Xu and Kamide, 2004). Indeed, this approach guarantees that the number of parameters used to represent the physical process is small as much as possible, and consequently process control for such system becomes apparent. We focus our present study on the analysis of the hourly means of the magnetic elements H, D and Z recorded at L’Aquila observatory in Italy from 1993 to 2004. We apply to this dataset the NOC technique to reconstruct the 3-dimensional structures of the different ionospheric and magnetospheric current systems which contribute to the geomagnetic daily variations. To support our interpretation in terms of the different ionospheric and magnetospheric current systems, the spectral and statistical features of the timedependent amplitudes associated to the set of natural orthogonal components are analyzed and compared to those of a set of descriptors of the magnetospheric dynamics and solar wind changes.221 184 - PublicationOpen AccessAuroral oval layers detection by using CSES plasma and electric field dataIonospheric medium fluctuations are detected at various spatial and temporal scales. Plasma irregularities encountered crossing high latitude current systems can be extremely thin and, therefore, unlikely to identify with standard detectors. This work aims to show plasma layer features obtained by electric field instrument on-board the Chinese Seismo Electromagnetic Satellite while crossing the equatorward boundary of the auroral oval allowing the characterization of its various layer. In addition, we made the multi-scale statistical analysis in order to describe the fluctuations of the ionospheric medium.
38 18 - PublicationOpen AccessOn the nonstationarity of the decadal periodicities of the length of day(2013-12-20)
; ; ; ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Tozzi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Consolini, G.; INAF – Istituto di Astrofisica e Planetologia Spaziali, 00133 Rome, Italy; ; The Earth's rotation rate is not constant, but changes on all observable timescales, from subdaily to decadal and longer. These variations are usually discussed in terms of variations in the length of the day (LoD) and are caused by processes acting within the interior, at the surface and outside of the Earth. Here, we investigate the presence of long-standing decadal variations in yearly LoD data covering the period from 1832 to 2009 by applying the Hilbert–Huang transform (HHT). The HHT has been slightly modified here to take into account the uncertainty of LoD values that has changed greatly in time due to the use of different LoD measurement techniques. The LoD time series has been completely decomposed into five intrinsic mode functions (IMF) and a residual trend. The estimation of instantaneous frequencies and related amplitudes of the obtained IMFs has allowed us to compute the Hilbert spectrum that has been used as the starting point for studying and discussing the stationarity of typical LoD timescale stationarity. The obtained results while showing the presence of multiple periodicities also indicate the absence of really stationary periodicities. Therefore, rather than considering the processes taking place in the Earth's core as the result of a superposition of oscillations (i.e. stationary mechanisms) occurring on a discrete number of different timescales, it would be better to think of a superposition of fluctuations that are intermittent in both frequency and amplitude.487 184 - PublicationOpen AccessStatistical behaviour of a proxy of the entropy production rate of the solar photosphereThe solar photosphere provides an incomparable laboratory to study turbulent convection in a dissipative non-equilibrium system. The evaluation of the entropy production rate on the solar photosphere and its probability distribution are the key issues for studying the non-equilibrium dynamics of the solar convection. The local entropy production rate is not offhandedly measurable on the solar photosphere, but it can be easily evaluated using the vertical heat flux as a proxy, which is given by the product between the line-of-sight velocity and the surface temperature. In this work, we present some preliminary results on statistics of the local entropy production rate via the vertical heat flux, using line-of-sight velocity and temperature maps of the solar photosphere which are derived from high-resolution spectro-polarimetric data making use of the Center of Gravity Method and the Stefan-Boltzmann law.
107 14 - PublicationOpen AccessDynamical Complexity of the 2015 St. Patrick’s Day Magnetic Storm at Swarm Altitudes Using Entropy Measures(2020-04)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The continuously expanding toolbox of nonlinear time series analysis techniques has recently highlighted the importance of dynamical complexity to understand the behavior of the complex solar wind–magnetosphere–ionosphere–thermosphere coupling system and its components. Here, we apply new such approaches, mainly a series of entropy methods to the time series of the Earth’s magnetic field measured by the Swarm constellation. We show successful applications of methods, originated from information theory, to quantitatively study complexity in the dynamical response of the topside ionosphere, at Swarm altitudes, focusing on the most intense magnetic storm of solar cycle 24, that is, the St. Patrick’s Day storm, which occurred in March 2015. These entropy measures are utilized for the first time to analyze data from a low-Earth orbit (LEO) satellite mission flying in the topside ionosphere. These approaches may hold great potential for improved space weather nowcasts and forecasts.365 20 - PublicationRestrictedMultifractality and Punctuated Equilibrium in the Earth's Magnetic Field Polarity Reversals(2000-01-15)
; ; ; ;Consolini, G.; Istituto di Fisica dello Spazio Interplanetario CNR, 00133 Roma, Italy ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Meloni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;; The Earth's magnetic field has reversed its polarity hundreds of times in the Earth's history. This phenomenon is generally viewed as due to a Poisson nonstationary process. Here, the geomagnetic chron time length sequence for the past 166 Ma, is analyzed using a multifractal approach, based on "singularity analysis". The existence of a multifractal structure is the signature of the occurrence of "punctuated equilibrium", which can be read as an indication of a critical configuration of the geodynamo. The results obtained are compared with those from a prototypical model of a dynamical system, introduced by Seki & Ito [1993], and are discussed in the context of fluid motions within the Earth's outer liquid core.190 23 - PublicationOpen AccessFrom the Sun to Earth: effects of the 25 August 2018 geomagnetic storm(2020-06-10)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; On 25 August 2018 the interplanetary counterpart of the 20 August 2018 coronal mass ejection (CME) hit Earth, giving rise to a strong G3 geomagnetic storm. We present a description of the whole sequence of events from the Sun to the ground as well as a detailed analysis of the observed effects on Earth’s environment by using a multi-instrumental approach. We studied the ICME (interplanetary-CME) propagation in interplanetary space up to the analysis of its effects in the magnetosphere, ionosphere and at ground level. To accomplish this task, we used groundand space-collected data, including data from CSES (China Seismo-Electric Satellite), launched on 11 February 2018. We found a direct connection between the ICME impact point on the magnetopause and the pattern of Earth’s auroral electrojets. Using the Tsyganenko TS04 model prevision, we were able to correctly identify the principal magnetospheric current system activating during the different phases of the geomagnetic storm. Moreover, we analysed the space weather effects associated with the 25 August 2018 solar event in terms of the evaluation of geomagnetically induced currents (GICs) and identification of possible GPS (Global Positioning System) losses of lock.We found that, despite the strong geomagnetic storm, no loss of lock had been detected. On the contrary, the GIC hazard was found to be potentially more dangerous than other past, more powerful solar events, such as the 2015 St Patrick’s Day geomagnetic storm, especially at latitudes higher than 60 in the European sector.563 39 - PublicationOpen Access“Multi-scale nature of the high-latitude magnetic field fluctuations”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.
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