Gradient pattern analysis of short solar radio bursts

Rosa, Reinaldo R.; Karlický, M.; Veronese, Thalita; Vijaykumar, Nandamudi Lankalapalli; Sawant, H. S.; Borgazzi, A.; Dantas, M.S.; Barbosa, Eduardo B. M.; Сыч, Р. А.; Mendes, Odim

doi:10.1016/j.asr.2007.08.015

Cited by 14 publications

(15 citation statements)

References 38 publications

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“…Also new data analysis approaches more robust against spuricus statistical fluctuations can be addressed in our work (e.g. Chang and Wu, 2008;Rosa et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Multifractal analysis of low-latitude geomagnetic fluctuations

2009

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Abstract.The technique of large deviation multifractal spectrum has shown that the high-latitude (77.5 • N, 69.2 • W) geomagnetic fluctuations can be described from direct dissipation process or loading-unloading regimes of the solar windmagnetosphere coupling. In this paper, we analyze the Hcomponent of low-latitude (22.4 • S, 43.6 • W) geomagnetic field variability observed during the month of July 2000 at the Geomagnetic Observatory, Vassouras, RJ, Brazil. The variability pattern during this period is a mixture of quiet and disturbed days including the Bastille Day intense geomagnetic storm on 15 July. Due to the complexity of this data, we pursue a detailed analysis of the geomagnetic fluctuations in different time scales including a multifractal approach using the singular power spectrum deviations obtained from the wavelet transform modulus maxima (WTMM). The results suggest, as observed from high-latitude data, the occurrence of low-latitude multifractal processes driving the intermittent coupling between the solar wind-magnetosphere and geomagnetic field variations. On finer scales possible physical mechanisms in the context of nonlinear magnetosphere response are discussed.

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“…Also new data analysis approaches more robust against spuricus statistical fluctuations can be addressed in our work (e.g. Chang and Wu, 2008;Rosa et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Multifractal analysis of low-latitude geomagnetic fluctuations

2009

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“…Recently, it was shown that decimetric solar bursts observed at 3 GHz due to mutual interacting solar loop with non-linear oscillations require models considering both anisotropy and intermittency. Thus, in the phenomenological analysis of the 3 GHz solar flare considering the scenario given in our previous papers (Rosa et al, 2008), we investigate energy spectra from intermittent MHD turbulent-like stochastic variability patterns with b ¼ 2 (weak turbulence) and b ¼ 5=3 (strong turbulence). Here the inhomogeneous nature of the decimetric solar radio emission was successfully detected by using the DFA method on the whole SRB time series.…”

Section: Discussionmentioning

confidence: 99%

“…The diagnostic potential of PSD and DFA methods is tested on a sub-set of Brownian noise time series. The canonical Brownian noise (fBm) proxy time series was generated from the stochastic system as given by Osborne and Provenzale (1989) (see Rosa et al, 2008 …”

Section: Psd and Dfamentioning

confidence: 99%

“…In particular, solar radio emissions in the decimetric frequency range (above 1 GHz) are very rich in temporal and spectral fine structures due to non-linear processes occurring in the magnetic structures on the corresponding active regions (Aschwanden et al, 1995). The importance of this decimetric solar flare scenario has been investigated, for example, from non-linear analysis of decimetric bursts at 3 GHz observed during the June 6, 2000 flare (Rosa et al, 2008). It was found that the 3 GHz radio burst power spectrum exhibits a power-law which is an evidence of stochastic intermittency due to a self-affine dynamics as found in the MHD turbulence theory.…”

Section: Introductionmentioning

confidence: 99%

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Fluctuation analysis of solar radio bursts associated with geoeffective X-class flares

Veronese

Rosa

Bolzan

et al. 2011

Journal of Atmospheric and Solar-Terrestrial Physics

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a b s t r a c tHigh temporal resolution solar observations in the decimetric range (1-3 GHz) can provide additional information on solar active regions dynamics and thus contribute to better understanding of solar geoeffective events as flares and coronal mass ejections. The June 6, 2000 flares are a set of remarkable geoeffective eruptive phenomena observed as solar radio bursts (SRB) by means of the 3 GHz Ondrejov Observatory radiometer. We have selected and analyzed, applying detrended fluctuation analysis (DFA), three decimetric bursts associated to X1.1, X1.2 and X2.3 flare-classes, respectively. The association with geomagnetic activity is also reported. DFA method is performed in the framework of a radio burst automatic monitoring system. Our results may characterize the SRB evolution, computing the DFA scaling exponent, scanning the SRB time series by a short windowing before the extreme event. For the first time, the importance of DFA in the context of SRB monitoring analysis is presented.

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“…The technique known as gradient pattern analysis (GPA), originally formulated to analyze spatiotemporal data (Rosa et al, 1999), was adapted to analyze patterns of asymmetries that appear exclusively in the time domain (Assireu et al, 2002). The GPA for time series (known as "GPA-1D") compares amplitude values considering different scales of time fluctuation mapped in its gradient field (Rosa et al, 2008). Within the scope of the GPA-1D, the value of the gradient asymmetry coefficient can also present relations with the values obtained from DFA, power spectra and fractal measures.…”

Section: Discussionmentioning

confidence: 99%

Nonlinear fluctuation analysis for a set of 41 magnetic clouds measured by the Advanced Composition Explorer (ACE) spacecraft

González

Mendes

et al. 2014

Nonlin. Processes Geophys.

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Abstract. The statistical distribution of values in the signal and the autocorrelations (interpreted as the memory or persistence) between values are attributes of a time series. The autocorrelation function values are positive in a time series with persistence, while they are negative in a time series with anti-persistence. The persistence of values with respect to each other can be strong, weak, or nonexistent. A strong correlation implies a "memory" of previous values in the time series. The long-range persistence in time series could be studied using semivariograms, rescaled range, detrended fluctuation analysis and Fourier spectral analysis, respectively. In this work, persistence analysis is to study interplanetary magnetic field (IMF) time series. We use data from the IMF components with a time resolution of 16 s. Time intervals corresponding to distinct processes around 41 magnetic clouds (MCs) in the period between March 1998 and December 2003 were selected. In this exploratory study, the purpose of this selection is to deal with the cases presenting the three periods: plasma sheath, MC, and post-MC. We calculated one exponent of persistence (e.g., α, β, Hu, Ha) over the previous three time intervals. The persistence exponent values increased inside cloud regions, and it was possible to select the following threshold values: α (j ) = 1.392, Ha (j ) = 0.327, and Hu (j ) = 0.875. These values are useful as another test to evaluate the quality of the identification. If the cloud is well structured, then the persistence exponent values exceed thresholds. In 80.5 % of the cases studied, these tools were able to separate the region of the cloud from neighboring regions. The Hausdorff exponent (Ha) provides the best results.

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Gradient pattern analysis of short solar radio bursts

Cited by 14 publications

References 38 publications

Multifractal analysis of low-latitude geomagnetic fluctuations

Multifractal analysis of low-latitude geomagnetic fluctuations

Fluctuation analysis of solar radio bursts associated with geoeffective X-class flares

Nonlinear fluctuation analysis for a set of 41 magnetic clouds measured by the Advanced Composition Explorer (ACE) spacecraft

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