@PhDThesis{Souza:2015:LoLaSc,
author = "Souza, Vitor Moura Cardoso e Silva",
title = "Location of large scale reconnection at Earth's dayside
magnetopause as probed by analytical X-line models and in situ
observations",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2015",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2015-02-24",
keywords = "reconex{\~a}o magn{\'e}tica, magnetopausa diurna, magnetosfera
terrestre, magnetic reconnection, dayside magnetopause, Earth's
magnetosphere.",
abstract = "The magnetic reconnection process is believed to occur throughout
the Universe whenever distinct magnetized plasma regimes come
together and interact. It has also been shown to be the dominant
process for the solar wind-magnetosphere interaction. In this work
the large scale aspect of the magnetic field reconnection process
is investigated: where does reconnection occur along the
Earth\${'}\$s dayside magnetopause and what are the key
parameters governing its location? We perform an intercomparison
of three analytical model\${'}\$s, which predict the
reconnection X-line location and orientation, namely Trattner et
al. (2007), Gonzalez and Mozer (1974), and Swisdak and Drake
(2007) against two sets of reconnection events which are
identified mostly by the in situ detection of accelerated plasma
flows. In the first set, we show four fortuitous,
quasi-simultaneous dayside magnetopause crossing events where two
widely separated spacecraft detect reconnection signatures, and
the possible X-line location can be inferred from the
observations. The X-line models are then used and their
predictions are compared with the expected X-line location
obtained from observation. The results suggest that an extended (>
5 Earth radii in length), component-type reconnection X-line may
in fact be a likely scenario at Earth\${'}\$s dayside
magnetopause, connecting and structuring the reconnection
characteristics on far apart observation points. In the second set
of reconnection events, we have analyzed the X-line models
performance in predicting the observed reconnection outflow
direction, i.e., its north-south and/or east-west senses, in a
total of 116 single magnetopause crossing events where
reconnection-generated plasma flows were clearly present. We found
that the Swisdak and Drake (2007)s X-line model had a slightly
better performance in predicting both accelerated plasma flow
components: north-south (72\% of the cases) and east-west (54\%
of the cases), as compared to the Trattner et al. (2007) model
(66\% north-south, 37\% east-west), and Gonzalez and Mozer
(1974) model (60\% north-south, 42\% east-west). The Swisdak and
Drake (2007) model takes into account the realistic asymmetrical
magnetic fields and plasma density conditions across the
magnetopause boundary layer, thus the result suggests that in
addition to external boundary conditions such as the
interplanetary magnetic field orientation and solar wind dynamic
pressure value, the local plasma and magnetic field conditions
play an important role in determining the large scale X-line
orientation at Earth\${'}\$s dayside magnetopause, in particular
the local plasma \$\beta\$, as it has been shown elsewhere
(PHAN et al., 2013). RESUMO: Acredita-se que o processo de
reconex{\~a}o magn{\'e}tica seja capaz de ocorrer por todo o
Universo toda vez que plasmas magnetizados distintos interajam.
Tem-se tamb{\'e}m mostrado que a reconex{\~a}o magn{\'e}tica
{\'e} o processo dominante na intera{\c{c}}{\~a}o vento
solar-magnetosfera terrestre. Neste trabalho, o aspecto de larga
escala do processo de reconex{\~a}o magn{\'e}tica {\'e}
investigado. Em particular, busca-se identificar em qual(is)
regi{\~a}o({\~o}es) ao longo da magnetopausa diurna terrestre a
reconex{\~a}o magn{\'e}tica ocorre, e ainda quais os
par{\^a}metros-chave que ditam o modo como a linha X deve
localizar-se. Utilizando dois conjuntos de eventos de
reconex{\~a}o magn{\'e}tica, os quais s{\~a}o identificados
principalmente pela detec{\c{c}}{\~a}o de fluxos de plasma
acelerados, faz-se uma compara{\c{c}}{\~a}o entre tr{\^e}s
modelos anal{\'{\i}}ticos: Trattner et al. (2007), Gonzalez and
Mozer (1974), and Swisdak and Drake (2007), que predizem a
localiza{\c{c}}{\~a}o e orienta{\c{c}}{\~a}o da linha X de
reconex{\~a}o. No primeiro conjunto de eventos, mostram-se quatro
eventos fortuitos de cruzamentos quasi-simult{\^a}neos da
magnetopausa diurna terrestre nos quais dois sat{\'e}lites
amplamente espa{\c{c}}ados detectam assinaturas de
reconex{\~a}o, e como a localiza{\c{c}}{\~a}o da prov{\'a}vel
linha X pode ser inferida atrav{\'e}s das
observa{\c{c}}{\~o}es. Os modelos de linha X s{\~a}o ent{\~a}o
utilizados e suas respectivas predi{\c{c}}{\~o}es comparadas com
a localiza{\c{c}}{\~a}o esperada da linha X. Os resultados
sugerem que uma extensa (> 5 raios terrestres em comprimento)
linha X de reconex{\~a}o por componente pode de fato constituir
um cen{\'a}rio prov{\'a}vel na magnetopausa diurna terrestre.
Tal linha conectaria e estruturaria as assinaturas de
reconex{\~a}o detectadas em pontos substancialmente distantes. No
segundo conjunto de eventos de reconex{\~a}o, analizou-se a
performance dos modelos de linha X em prever a
dire{\c{c}}{\~a}o, isto {\'e}, sentidos norte-sul e/ou
leste-oeste, dos plasmas acelerados em 116 eventos de cruzamentos
simples (somente um sat{\'e}lite) pela magnetopause diurna
terrestre para os quais os fluxos de plasma provenientes do
processo de reconex{\~a}o estivessem claramente presentes.
Encontrou-se que o modelo de linha X de Swisdak and Drake (2007)
obteve uma performance ligeiramente melhor na predi{\c{c}}{\~a}o
de ambas as componentes dos plasmas acelerados: norte-sul (72\%
dos casos) e leste-oeste (54\% dos casos), quando comparado com o
modelo de Trattner et al. (2007) (66\% norte-sul, 37\%
leste-oeste), e o modelo de Gonzalez and Mozer (1974) (60\%
norte-sul, 42\% leste-oeste). O modelo de Swisdak and Drake
(2007) leva em considera{\c{c}}{\~a}o condi{\c{c}}{\~o}es
real{\'{\i}}sticas de assimetrias nos campos magn{\'e}ticos e
densidades do plasma atrav{\'e}s da magnetopausa, portanto o
resultado acima sugere que al{\'e}m de condi{\c{c}}{\~o}es de
contorno externas, tais como a orienta{\c{c}}{\~a}o do campo
magn{\'e}tico interplanet{\'a}rio e o valor da press{\~a}o
din{\^a}mica do vento solar, as condi{\c{c}}{\~o}es locais de
campo magn{\'e}tico e plasma, em particular o par{\^a}metro
\$\beta\$, possuem papel fundamental na
determina{\c{c}}{\~a}o da orienta{\c{c}}{\~a}o da linha X de
larga escala na magnetopausa diurna terrestre, como tem sido
mostrado na literatura (PHAN et al., 2013).",
committee = "Dal Lago, Alisson (presidente) and Koga, Daiki (orientador) and
Mendes Junior, Odim (orientador) and Dallaqua, Renato S{\'e}rgio
and Sibeck, David Gary and Cardoso, Fl{\'a}via Reis",
copyholder = "SID/SCD",
englishtitle = "An{\'a}lise da localiza{\c{c}}{\~a}o da reconex{\~a}o
magn{\'e}tica em larga escala na magnetopausa diurna terrestre
por meio de modelos anal{\'{\i}}ticos de linha X e
observa{\c{c}}{\~o}es in situ",
language = "en",
pages = "212",
ibi = "8JMKD3MGP3W34P/3J3GFGP",
url = "http://urlib.net/ibi/8JMKD3MGP3W34P/3J3GFGP",
targetfile = "publicacao.pdf",
urlaccessdate = "27 abr. 2024"
}