The magnetosphere as a complex system

Valdivia, J. A.; Rogan, José; Muñoz, Vı́ctor; Gomberoff, L.; Klimas, A. J.; Vassiliadis, D.; Uritsky, V. M.; Sharma, Surja; Toledo, B. A.; Wastavino, L.

doi:10.1016/j.asr.2005.03.144

Cited by 38 publications

(40 citation statements)

References 68 publications

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“…In particular, it has been suggested that various magnetized plasma systems are in a self-organized critical state, exhibiting fractal and multifractal features which relate them to a broader class of complex systems. This has been the case in studies on the Earth's magnetosphere (Chang, 1999;Valdivia et al, 2005Valdivia et al, , 2003Valdivia et al, , 2006Valdivia et al, , 2013, the solar wind (Macek, 2010), the solar photosphere, and solar corona (Berger and Asgari-Targhi, 2009;Dimitropoulou et al, 2009). Some authors have discussed the relationship between the fractal dimension and physical processes in magnetized plasmas in the Sun-Earth system, including the possibility of forecasting geomagnetic activity (Aschwanden and Aschwanden, 2008;Uritsky et al, 2006;Georgoulis, 2012;McAteer et al, 2005McAteer et al, , 2010Dimitropoulou et al, 2009;Conlon et al, 2008;Chapman et al, 2008;Kiyani et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Evolution of fractality in space plasmas of interest to geomagnetic activity

Muñoz

Domínguez

Valdivia

et al. 2018

Nonlin. Processes Geophys.

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Abstract. We studied the temporal evolution of fractality for geomagnetic activity, by calculating fractal dimensions from the Dst data and from a magnetohydrodynamic shell model for turbulent magnetized plasma, which may be a useful model to study geomagnetic activity under solar wind forcing. We show that the shell model is able to reproduce the relationship between the fractal dimension and the occurrence of dissipative events, but only in a certain region of viscosity and resistivity values. We also present preliminary results of the application of these ideas to the study of the magnetic field time series in the solar wind during magnetic clouds, which suggest that it is possible, by means of the fractal dimension, to characterize the complexity of the magnetic cloud structure.

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Section: Introductionmentioning

confidence: 99%

Evolution of fractality in space plasmas of interest to geomagnetic activity

Muñoz

Domínguez

Valdivia

et al. 2018

Nonlin. Processes Geophys.

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“…At this location, the actions of X-ray, ultraviolet, and another wavelengths from the Sun are 132 M. J. A. Bolzan et al: Multifractal analysis of VTEC at equatorial region and low latitude more direct, strong, and constant throughout the year, compared with SJC, which is situated at 23 • S. This fact could explain the higher values found for the µ parameter for Belém compared with SJC, even though the last site is near IEA peaks (Walker, 1981;Walker and Strickland, 1981).…”

Section: Discussionmentioning

confidence: 54%

“…The SJC site is near −20 • (−23 • in fact) and would have strong influence from the IEA, resulting in higher values of the µ parameter compared to the Belém site. However, it is important to mention that we analysed data sets obtained from low solar activity periods, 2006 and 2007, and the IEA would not be strong compared with high solar activity period, as studied by Walker (1981) and Walker and Strickland (1981). This fact could explain the higher values found for the µ parameter for Belém compared with SJC, even though the last site is near IEA peaks.…”

Section: Results and Interpretationmentioning

confidence: 83%

“…period of 1 h (see Table 1). Walker (1981) and Walker and Strickland (1981) showed that the region between −20 • and +20 • of geomagnetic latitude experiences a phenomenon called ionospheric equatorial anomaly (IEA), which is an important source of intermittence due to the presence of the VTEC peaks at geomagnetic latitudes. The SJC site is near −20 • (−23 • in fact) and would have strong influence from the IEA, resulting in higher values of the µ parameter compared to the Belém site.…”

Section: Results and Interpretationmentioning

confidence: 99%

“…In addition, the VTEC time series depend on geomagnetic substorm and storm activities. The two distinct observations of a global self-organized state (SO) and a repetitive state promoted by substorm cycle (Valdivia et al, 2005) show that the geomagnetic system is complex. According to Bolzan et al (2009b), these problems have external origin due to the Sun-Earth interactions (Gonzales et al, 2002) along with internal origins such as gravity and planetary waves .…”

Section: Introductionmentioning

confidence: 99%

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Multifractal analysis of vertical total electron content (VTEC) at equatorial region and low latitude, during low solar activity

et al. 2013

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Abstract. This paper analyses the multifractal aspects of the GPS data (measured during a period of low solar activity) obtained from two Brazilian stations: Belém (01.3 • S, 48.3 • W) and São José dos Campos (SJC) (23.2 • S, 45.9 • W). The results show that the respective geographic sites show important scaling differences as well as similarities when their multifractal signatures for vertical total electron content (VTEC) are compared. The f (α) spectra have a narrow shape for great scales, which indicates the predominance of deterministic phenomena, such as solar rotation (27 days) over intermittent phenomena. Furthermore, the f (α) spectra for both sites have a strong multifractality degree at small scales. This strong multifractality degree observed at small scales (1 to 12 h) at both sites is because the ionosphere over Brazil is a non-equilibrium system. The differences found were that Belém presented a stronger multifractality at small scales (1 h to 12 h) compared with SJC, particularly in 2006. The reason for this behaviour may be associated with the location of Belém, near the geomagnetic equator, where at this location the actions of X-rays, ultraviolet, and another wavelength from the Sun are more direct, strong, and constant throughout the whole year. Although the SJC site is near ionospheric equatorial anomaly (IEA) peaks, this interpretation could explain the higher values found for the intermittent parameter µ for Belém compared with SJC. Belém also showed the presence of one or two flattening regions for f (α) spectra at the same scales mentioned before. These differences and similarities also were interpreted in terms of the IEA content, where this phenomenon is an important source of intermittence due the presence of the VTEC peaks at ±20 • geomagnetic latitudes.

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Temporal evolution of fractality in the Earth's magnetosphere and the solar photosphere

2014

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Citation:Domínguez, M., V. Muñoz, and J. A. Valdivia (2014), Temporal evolution of fractality in the Earth's magnetosphere and the solar photosphere, Abstract The study of complexity in two aspects of the magnetic activity in the Sun-Earth system is presented. We compare the temporal evolution of the magnetic fluctuations in the Earth's magnetosphere and the spatial distribution of the magnetic field in the solar photosphere, by calculating fractal dimensions from the data. It is found that the fractal dimension of the Dst data decreases during magnetic storm states and is well correlated with other indexes of solar activity, such as the solar flare and coronal indexes. This correlation holds for individual storms, full-year data, and the complete 23rd solar cycle. The fractal dimension from solar magnetogram data also correlates well with both the Dst index and solar flare index, although the correlation is much more clear at the larger temporal scale of the 23rd solar cycle, showing a clear increase around solar maximum.The main objective of this work is to characterize the occurrence of events such as geomagnetic storms and solar flares by means of a fractal dimension, as a way to measure the complexity of magnetic field time series and spatial patterns. In this context, we analyze the possible time correlation between the calculated fractal dimensions and various indexes of geomagnetic and solar dynamics.In particular, we calculate a box-counting fractal dimension [Addison, 1997], because of its simplicity and its intuitive meaning. Although the box-counting algorithm can provide only partial information on the complexity of the systems, in particular when they also exhibit multifractality as in our case, it is able to describe some features of solar and geomagnetic complexity as we will show below, and in fact it has also been successfully used in other studies of the Sun-Earth system [Osella et al.

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The magnetosphere as a complex system

Cited by 38 publications

References 68 publications

Evolution of fractality in space plasmas of interest to geomagnetic activity

Evolution of fractality in space plasmas of interest to geomagnetic activity

Multifractal analysis of vertical total electron content (VTEC) at equatorial region and low latitude, during low solar activity

Temporal evolution of fractality in the Earth's magnetosphere and the solar photosphere

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