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Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations

The solar photosphere and the outer layer of the Sun’s interior are characterized by convective motions, which display a chaotic and turbulent character. In this work, we evaluated the pseudo-Lyapunov exponents of the overshooting convective motions observed on the Sun’s surface by using a method em...

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Autores principales: Viavattene, Giorgio, Murabito, Mariarita, Guglielmino, Salvatore L., Ermolli, Ilaria, Consolini, Giuseppe, Giorgi, Fabrizio, Jafarzadeh, Shahin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8065511/
https://www.ncbi.nlm.nih.gov/pubmed/33807240
http://dx.doi.org/10.3390/e23040413
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author Viavattene, Giorgio
Murabito, Mariarita
Guglielmino, Salvatore L.
Ermolli, Ilaria
Consolini, Giuseppe
Giorgi, Fabrizio
Jafarzadeh, Shahin
author_facet Viavattene, Giorgio
Murabito, Mariarita
Guglielmino, Salvatore L.
Ermolli, Ilaria
Consolini, Giuseppe
Giorgi, Fabrizio
Jafarzadeh, Shahin
author_sort Viavattene, Giorgio
collection PubMed
description The solar photosphere and the outer layer of the Sun’s interior are characterized by convective motions, which display a chaotic and turbulent character. In this work, we evaluated the pseudo-Lyapunov exponents of the overshooting convective motions observed on the Sun’s surface by using a method employed in the literature to estimate those exponents, as well as another technique deduced from their definition. We analyzed observations taken with state-of-the-art instruments at ground- and space-based telescopes, and we particularly benefited from the spectro-polarimetric data acquired with the Interferometric Bidimensional Spectrometer, the Crisp Imaging SpectroPolarimeter, and the Helioseismic and Magnetic Imager. Following previous studies in the literature, we computed maps of four quantities which were representative of the physical properties of solar plasma in each observation, and estimated the pseudo-Lyapunov exponents from the residuals between the values of the quantities computed at any point in the map and the mean of values over the whole map. In contrast to previous results reported in the literature, we found that the computed exponents hold negative values, which are typical of a dissipative regime, for all the quantities derived from our observations. The values of the estimated exponents increase with the spatial resolution of the data and are almost unaffected by small concentrations of magnetic field. Finally, we showed that similar results were also achieved by estimating the exponents from residuals between the values at each point in maps derived from observations taken at different times. The latter estimation technique better accounts for the definition of these exponents than the method employed in previous studies.
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spelling pubmed-80655112021-04-25 Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations Viavattene, Giorgio Murabito, Mariarita Guglielmino, Salvatore L. Ermolli, Ilaria Consolini, Giuseppe Giorgi, Fabrizio Jafarzadeh, Shahin Entropy (Basel) Article The solar photosphere and the outer layer of the Sun’s interior are characterized by convective motions, which display a chaotic and turbulent character. In this work, we evaluated the pseudo-Lyapunov exponents of the overshooting convective motions observed on the Sun’s surface by using a method employed in the literature to estimate those exponents, as well as another technique deduced from their definition. We analyzed observations taken with state-of-the-art instruments at ground- and space-based telescopes, and we particularly benefited from the spectro-polarimetric data acquired with the Interferometric Bidimensional Spectrometer, the Crisp Imaging SpectroPolarimeter, and the Helioseismic and Magnetic Imager. Following previous studies in the literature, we computed maps of four quantities which were representative of the physical properties of solar plasma in each observation, and estimated the pseudo-Lyapunov exponents from the residuals between the values of the quantities computed at any point in the map and the mean of values over the whole map. In contrast to previous results reported in the literature, we found that the computed exponents hold negative values, which are typical of a dissipative regime, for all the quantities derived from our observations. The values of the estimated exponents increase with the spatial resolution of the data and are almost unaffected by small concentrations of magnetic field. Finally, we showed that similar results were also achieved by estimating the exponents from residuals between the values at each point in maps derived from observations taken at different times. The latter estimation technique better accounts for the definition of these exponents than the method employed in previous studies. MDPI 2021-03-31 /pmc/articles/PMC8065511/ /pubmed/33807240 http://dx.doi.org/10.3390/e23040413 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Viavattene, Giorgio
Murabito, Mariarita
Guglielmino, Salvatore L.
Ermolli, Ilaria
Consolini, Giuseppe
Giorgi, Fabrizio
Jafarzadeh, Shahin
Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations
title Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations
title_full Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations
title_fullStr Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations
title_full_unstemmed Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations
title_short Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations
title_sort analysis of pseudo-lyapunov exponents of solar convection using state-of-the-art observations
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8065511/
https://www.ncbi.nlm.nih.gov/pubmed/33807240
http://dx.doi.org/10.3390/e23040413
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