Solar and Interplanetary Turbulence: Lagrangian Coherent Structures

Talk delivered in 22nd EGU General Assembly, held online 4-8 May, 2020, id.4289, https://meetingorganizer.copernicus.org/EGU2020/EGU2020-4289.html.-- https://www.egu2020.eu/The dynamics of solar and interplanetary plasmas is governed by coherent structures such as current sheets and magnetic flux ropes which are responsible for the genesis of intermittent turbulence via magnetic reconnections in solar supergranular junctions, solar coronal loops, the shock-sheath region of an interplanetary coronal mass ejection, and the interface region of two interplanetary magnetic flux ropes. Lagrangian coherent structures provide a new powerful technique to detect time- or space-dependent transport barriers, and objective (i.e., frame invariant) kinematic and magnetic vortices in space plasma turbulence. We discuss the basic concepts of Lagrangian coherent structures in plasmas based on the computation of the finite-time Lyapunov exponent, the Lagrangian averaged vorticity deviation and the integrated averaged current deviation, as well as their applications to numerical simulations of MHD turbulence and space and ground observations.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation SEV-2017-070

Toxicity effects of magnesium oxide nanoparticles: a brief report

In this work, magnesium oxide nanoparticles were synthesized by the sol-gel route and their ecotoxicity was tested in worms of the Eisenia andrei species. Magnesium oxide nanoparticles were characterized by XRD, surface area via BET, TEM and SEM-FEG/EDS. The lethality test with Eisenia andrei earthworm species followed the recommendations of ISO 11268-1 (ISO, 2012) in a completely randomized design with six replicates for each concentration tested (1.06, 2.12, 4.24, 8.48 and 16.96 μg of NPs-MgO/kg of soil), plus the control. The concentrations were mixed to the tropical natural soils, Entisol Typic Quartzipsamments and Oxisol, with no agricultural use history. The morphological and structural analyses of the nanoparticles indicated the formation of magnesium oxide with cubic structure, constituting agglomerates of nanostructures of the order of 20 to 50 nm. The results of toxicity were submitted to analysis of variance (ANOVA One-way), followed by the Dunnett test (p 0.05). Based on standardized toxicological tests it was found that NPs-MgO, at the concentrations tested, did not affect the survival of Eisenia andrei species in the natural soils studied.Keywords: Terrestrial toxicity of nanoparticles, edaphic fauna, Terrestrial toxicity of magnesium oxide nanoparticles.

Lagrangian chaotic saddles and objective vortices in solar plasmas

We report observational evidence of Lagrangian chaotic saddles in plasmas, given by the intersections of finite-time unstable and stable manifolds, using an approximate to 22h sequence of spacecraft images of the horizontal velocity field of solar photosphere. A set of 29 persistent objective vortices with lifetimes varying from 28.5 to 298.3 min are detected by computing the Lagrangian averaged vorticity deviation. The unstable manifold of the Lagrangian chaotic saddles computed for approximate to 11h exhibits twisted folding motions indicative of recurring vortices in a magnetic mixed-polarity region. We show that the persistent objective vortices are formed in the gap regions of Lagrangian chaotic saddles at supergranular junctions. ©2020 American Physical SocietyThis work was supported by Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES No. 88882.316962/2019-01 and No. 88881.309066/2018-01, Brazil), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, Brazil), NASA Contract No. NNM07AA01C [Solar-B (Hinode) Focal Plane Package Phase E], Ministerio de Ciencia, Innovacion y Universidades (No. RTI2018-096886-B-C51, Spain), European Regional Development Fund (FEDER), and Center of Excellence Severo Ochoa Award to the Instituto de Astrofisica de Andalucia (No. SEV-2017-0709, Spain).Peer reviewe

Intensification of magnetic field in merging magnetic flux tubes driven by supergranular vortical flows

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.The spatiotemporal dynamics of vorticity and magnetic field in the region of a photospheric vortex at a supergranular junction of the quiet Sun is studied, using Hinode’s continuum intensity images and longitudinal magnetograms. We show that in a 30-min interval during the vortex lifetime, the magnetic field is intensified at the centres of two merging magnetic flux tubes trapped inside the vortex boundary. Moreover, we show that the electric current density is intensified at the interface boundary layers of merging tubes, resulting from strong vortical downflows in a supergranular vertex. Evidence of Lagrangian chaos and vortex stretching in the photospheric plasma turbulence responsible for driving the intensification of magnetic fields is analysed. In particular, we report the first solar observation of the intensification of electromagnetic energy flux resulting from the merger of magnetic flux tubes. © 2022 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.The data used here were acquired in the framework of the Hinode Operation Plan 151 ‘Flux replacement in the solar network and internetwork’. Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as a domestic partner and NASA and STFC (UK) as international partners. Financial support by the State Agency for Research of the Spanish Ministerio de Ciencia e Innovación through grant RTI2018-096886-B-C5 (including FEDER funds) and through a Center of Excellence Severo Ochoa award to Instituto de Astrofísica de Andalucía (SEV-2017-0709) is gratefully acknowledged. SSAS is grateful to Science and Technology Facilities Council (STFC) grant ST/V000977/1, and The Royal Society, International Exchanges Scheme, collaboration with Brazil (IES191114). MG was supported by NASA contract NNM07AA01C (Solar-B (Hinode) Focal Plane Package Phase E). ELR acknowledges Brazilian agency CNPq (Grant 306920/2020-4) for the financial support.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe

O significado do cuidado para o adulto em condição crônica de saúde em consulta de enfermagem

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O significado do cuidado para o adulto em condição crônica de saúde em consulta de enfermagem

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Supergranular turbulence in the quiet Sun: Lagrangian coherent structures

The quiet Sun exhibits a wealth of magnetic activities that are fundamental for our understanding of solar magnetism. The magnetic fields in the quiet Sun are observed to evolve coherently, interacting with each other to form prominent structures as they are advected by photospheric flows. The aim of this paper is to study supergranular turbulence by detecting Lagrangian coherent structures (LCS) based on the horizontal velocity fields derived from Hinode intensity images at disc centre of the quiet Sun on 2010 November 2. LCS act as transport barriers and are responsible for attracting/repelling the fluid elements and swirling motions in a finite time. Repelling/attracting LCS are found by computing the forward/backward finite-time Lyapunov exponent (FTLE), and vortices are found by the Lagrangian-averaged vorticity deviation method. We show that the Lagrangian centres and boundaries of supergranular cells are given by the local maximum of the forward and backward FTLE, respectively. The attracting LCS expose the location of the sinks of photospheric flows at supergranular junctions, whereas the repelling LCS interconnect the Lagrangian centres of neighbouring supergranular cells. Lagrangian transport barriers are found within a supergranular cell and from one cell to other cells, which play a key role in the dynamics of internetwork and network magnetic elements. Such barriers favour the formation of vortices in supergranular junctions. In particular, we show that the magnetic field distribution in the quiet Sun is determined by the combined action of attracting/repelling LCS and vortices.© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical SocietySSAS acknowledges financial support from agency Coordenacao de aperfeicoamento de Pessoal de nivel Superior (CAPES 88882.316962/2019-01, Brazil). ELR acknowledges financial support from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, Brazil), partial financial support from CAPES (Brazil) and from Fundacao de Amparo a Pesquisa de Sao Paulo (FAPESP, Brazil). LBR acknowledges financial support from the Spanish Ministerio de Ciencia, Innovacion y Universidades through grant RTI2018-096886-B-C51, including a percentage from European Regional Development Fund (FEDER), and through the 'Center of Excellence Severo Ochoa' award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709).Peer reviewe

O significado do cuidado para o adulto em condição crônica de saúde em consulta de enfermagem

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O significado do cuidado para o adulto em condição crônica de saúde em consulta de enfermagem

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