@PhDThesis{Gomes:2019:EsCaVe,
author = "Gomes, Tiago Francisco Pinheiro",
title = "Eventos extremos e estruturas coerentes na turbul{\^e}ncia:
estudo de caso para o vento solar",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2019",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2018-10-19",
keywords = "vento solar, estruturas coerentes, eventos extremos,
turbul{\^e}ncia, v{\'o}rtices magn{\'e}ticos, solar wind,
coherent structures, extreme events, turbulence, magnetic
vortices.",
abstract = "Na presente tese, s{\~a}o aplicadas t{\'e}cnicas
estat{\'{\i}}sticas para modelagens de distribui{\c{c}}{\~o}es
de eventos extremos, detec{\c{c}}{\~a}o de l{\^a}minas de
correntes, an{\'a}lises de turbul{\^e}ncia intermitente e
detec{\c{c}}{\~a}o de Dragon Kings em dados observacionais e
simulados do vento solar. Mostramos que l{\^a}minas de correntes
s{\~a}o as estruturas coerentes respons{\'a}veis pela
presen{\c{c}}a de turbul{\^e}ncia bem desenvolvida de Kolmogorov
em s{\'e}ries temporais do m{\'o}dulo do campo magn{\'e}tico do
vento solar, al{\'e}m de serem as grandes respons{\'a}veis pela
positividade do par{\^a}metro de forma, principal par{\^a}metro
da teoria cl{\'a}ssica de valores extremos e respons{\'a}vel por
caracterizar o comportamento das caudas das
distribui{\c{c}}{\~o}es generalizadas de Pareto e de valores
extremos. Propomos uma nova t{\'e}cnica para detec{\c{c}}{\~a}o
de l{\^a}minas de correntes e reconex{\~o}es magn{\'e}ticas
baseada na volatilidade. Al{\'e}m disto, propomos uma prova
te{\'o}rica para a objetividade de uma nova t{\'e}cnica
lagrangiana de detec{\c{c}}{\~a}o de v{\'o}rtices
magn{\'e}ticos, validando sua utiliza{\c{c}}{\~a}o em plasmas
espaciais. Baseado no campo de velocidades, propomos uma nova
t{\'e}cnica euleriana e independente do referencial para
detec{\c{c}}{\~a}o de centros vorticais. Identificamos
inconsist{\^e}ncias em t{\'e}cnica lagrangiana e objetiva de
detec{\c{c}}{\~a}o de v{\'o}rtices baseados na vorticidade
quando aplicado em plasma solar, para o qual propomos uma
solu{\c{c}}{\~a}o. Para a modelagem estat{\'{\i}}stica de
eventos extremos, utilizamos a teoria cl{\'a}ssica de eventos
extremos, a qual se baseia nas t{\'e}cnicas de picos acima de um
limiar e de m{\'a}ximos em blocos. Para a simula{\c{c}}{\~a}o
de ambiente interplanet{\'a}rio, utilizamos simula{\c{c}}{\~a}o
MHD-3D compress{\'{\i}}vel, adiab{\'a}tica e com
for{\c{c}}ante n{\~a}o helicoidal. Fomos os primeiros a aplicar
com sucesso a teoria de Dragon Kings em dados do vento solar,
encontrando fortes evid{\^e}ncias de que reconex{\~o}es
magn{\'e}ticas pertencem a esta classe especial de eventos
extremos. Para as an{\'a}lises estat{\'{\i}}sticas de Dragon
Kings, utilizamos o teste-U, teste-DK e intervalos de
confian{\c{c}}a para distribui{\c{c}}{\~o}es de leis de
pot{\^e}ncia. ABSTRACT: In the present work, statistical
techniques are employed in the modelling of extreme events
distributions, detection of current sheets, analysis of
intermittent turbulence and detection of Dragon Kings in
observational and simulated solar wind data. We have shown that
current sheets are the principal coherent structures responsible
for the presence of Kolmogorov turbulence in solar wind time
series of the modulus of magnetic field, as well as being
responsible for the positivity of the shape parameter, the main
parameter of extreme values theory and responsible for
characterizing the tails behavior of generalized Pareto and
extreme values distributions. We propose a new technique for
detection of current sheets and magnetic reconnections based on
volatility. Additionally, we propose a mathematical proof for the
objectivity of a new technique for the detection of magnetic
vortices, validating its application in space plasmas. Based on
the velocity field, we propose a new frame invariant eulerian
technique for vortex centers detection. We identified
inconsistencies in lagrangian and objective vortex detection
technique based on vorticity when applied to solar plasma, for
which we propose a solution. For the statistical modelling of
extreme events, the classical theory of extreme events is adopted,
which is based on the peaks over threshold and block maxima
techniques. For the interplanetary environment simulation, 3D
compressible and adiabatic MHD simulations are used with a
nonhelical forcing. We were the first to successfully apply the
dragon kings theory to solar wind data, finding strong evidence
that magnetic reconnections belong to this special class of
extreme events. For the statistical analyses of Dragon Kings, the
U-test and the DK-test are adopted.",
committee = "Alves, Maria Virg{\'{\i}}nia (presidente) and Rempel, Erico Luiz
(orientador) and Long-Chian, Abraham Chian (orientador) and Ramos,
Fernando Manuel (orientador) and Dallaqua, Renato Sergio and
Cerda, Rodrigo Andr{\'e}s Miranda and Roberto, Marisa",
englishtitle = "Extreme events and coherent structures in turbulence: a case study
for the solar wind",
language = "pt",
pages = "271",
ibi = "8JMKD3MGP3W34R/3S94U7P",
url = "http://urlib.net/ibi/8JMKD3MGP3W34R/3S94U7P",
targetfile = "publicacao.pdf",
urlaccessdate = "28 mar. 2024"
}