Multifractal analysis of interplanetary magnetic field obtained during CME events

Bolzan, Maurı́cio José Alves; Rosa, Reinaldo R.

doi:10.5194/angeo-30-1107-2012

Cited by 19 publications

(15 citation statements)

References 35 publications

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“…We used the cross-wavelet transform to obtain the common periods between two time series and, also, to study the temporal variability of the main periods found (Bolzan et al, 2012). The XWT is given by (Grinsted et al, 2004)…”

Section: Cross-wavelet Analysismentioning

confidence: 99%

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

Souza

Echer

Bolzan³

et al. 2018

Ann. Geophys.

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Abstract. Solar-wind-geomagnetic activity coupling during high-intensity long-duration continuous AE (auroral electrojet) activities (HILDCAAs) is investigated in this work. The 1 min AE index and the interplanetary magnetic field (IMF) B z component in the geocentric solar magnetospheric (GSM) coordinate system were used in this study. We have considered HILDCAA events occurring between 1995 and 2011. Cross-wavelet and cross-correlation analyses results show that the coupling between the solar wind and the magnetosphere during HILDCAAs occurs mainly in the period ≤ 8 h. These periods are similar to the periods observed in the interplanetary Alfvén waves embedded in the high-speed solar wind streams (HSSs). This result is consistent with the fact that most of the HILDCAA events under present study are related to HSSs. Furthermore, the classical correlation analysis indicates that the correlation between IMF B z and AE may be classified as moderate (0.4-0.7) and that more than 80 % of the HILDCAAs exhibit a lag of 20-30 min between IMF B z and AE. This result corroborates with Tsurutani et al. (1990) where the lag was found to be close to 20-25 min. These results enable us to conclude that the main mechanism for solar-wind-magnetosphere coupling during HILDCAAs is the magnetic reconnection between the fluctuating, negative component of IMF B z and Earth's magnetopause fields at periods lower than 8 h and with a lag of about 20-30 min.

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Section: Cross-wavelet Analysismentioning

confidence: 99%

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

Souza

Echer

Bolzan³

et al. 2018

Ann. Geophys.

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“…where a is the scaling factor and W XY the cross-wavelet transform applied in two time series given by (Torrence and Compo, 1998;Bolzan and Vieira, 2006)…”

Section: Cross-wavelet Analysismentioning

confidence: 99%

Comparison of <i>H</i> component geomagnetic field time series obtained at different sites over South America

2018

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Abstract. The geomagnetic field in the Brazilian sector is influenced by the South American Magnetic Anomaly (SAMA) that causes a decrease in the magnitude of the local geomagnetic field when compared to other regions in the world. Thus, the magnetometer network and data set of space weather over Brazil led by Embrace are important tools for promoting the understanding of geomagnetic fields over Brazil. In this sense, in this work we used the H component of geomagnetic fields obtained at different sites in South America in order to compare results from the phase coherence obtained from wavelet transform (WT). Results from comparison between Cachoeira Paulista (CXP) and Eusébio (EUS), and Cachoeira Paulista and São Luis (SLZ), indicated that there exist some phenomena that occur simultaneously in both locations, putting them in the same phase coherence. However, there are other phenomena putting both locations in a strong phase difference as observed between CXP and Rio Grande, Argentina (RGA). This study was done for a specific moderate geomagnetic storm that occurred in March 2003. The results are explained in terms of nonlinear interaction between physical phenomena acting in distinct geographic locations and at different times and scales. Keywords. Geomagnetism and paleomagnetism (time variations – diurnal to secular)

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“…According to previous works (Bolzan et al, 2009a, b;Bolzan and Rosa, 2012), the vertical total electron content (VTEC) time series have very intermittent characteristics, mainly at small scales. In addition, the VTEC time series depend on geomagnetic substorm and storm activities.…”

Section: Introductionmentioning

confidence: 94%

“…This process provides the power-law for small α the scaling exponents τ (q) -the multifractal spectrum (Muzy et al, 1991). Arneodo et al (1995) used a hierarchy of the WTMM to obtain the partition function Z(a, q) based on the multifractal formalism.…”

Section: Multifractal Analysismentioning

confidence: 99%

“…Studying the relations between solar and geomagnetic/ionospheric phenomena on the Earth is important due to their consequences on human activities Bolzan and Rosa, 2012). Recently, global position system (GPS) satellites have been used to study the effects of solar disturbances on earth's geomagnetic field variations (Krankowski et al, 2005).…”

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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Multifractal analysis of interplanetary magnetic field obtained during CME events

Cited by 19 publications

References 35 publications

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

Comparison of <i>H</i> component geomagnetic field time series obtained at different sites over South America

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

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Multifractal analysis of interplanetary magnetic field obtained during CME events

Cited by 19 publications

References 35 publications

Cross-correlation and cross-wavelet analyses of the solar wind IMF Bz and auroral electrojet index AE coupling during HILDCAAs

Cross-correlation and cross-wavelet analyses of the solar wind IMF Bz and auroral electrojet index AE coupling during HILDCAAs

Comparison of &lt;i&gt;H&lt;/i&gt; component geomagnetic field time series obtained at different sites over South America

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

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Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

Cross-correlation and cross-wavelet analyses of the solar wind IMF B_z and auroral electrojet index AE coupling during HILDCAAs

Comparison of <i>H</i> component geomagnetic field time series obtained at different sites over South America