@PhDThesis{Guarnieri:2005:EsOrIn,
author = "Guarnieri, Fernando Lu{\'{\i}}s",
title = "Estudo da origem interplanet{\'a}ria e solar de eventos de
atividade auroral cont{\'{\i}}nua e de longa
dura{\c{c}}{\~a}o",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2005",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2005-02-22",
keywords = "geof{\'{\i}}sica espacial, atividade auroral, eletrojeto
auroral, auroras, vento solar, buracos coronais, tempo do
espa{\c{c}}o, ondas magnetohidrodin{\^a}micas, space geophysics,
auroral activity, auroral electrojets, auroras, solar wind,
coronal holes, space weather, magnetohydrodinamic waves.",
abstract = "Esta tese consistiu no estudo das causas solares e
interplanet{\'a}rias e das conseq{\"u}{\^e}ncias geoefetivas de
14 eventos HILDCAAs ocorridos entre os anos de 1998 e 2001. Estes
eventos foram usados por seguirem rigidamente os crit{\'e}rios de
sele{\c{c}}{\~a}o para este tipo de fen{\^o}meno. No meio
interplanet{\'a}rio os HILDCAAs est{\~a}o associados a feixes
r{\'a}pidos ricos em flutua{\c{c}}{\~o}es alfv{\'e}nicas. No
Sol, estes feixes t{\^e}m origem em buracos coronais, que foram
relacionados {\`a} ocorr{\^e}ncia de cada um dos eventos. Dados
de campo magn{\'e}tico do meio interplanet{\'a}rio e do
{\'{\i}}ndice AE tiveram suas periodicidades analisadas por
t{\'e}cnicas cl{\'a}ssicas, como espectro de pot{\^e}ncia, e
tamb{\'e}m por t{\'e}cnicas modernas, como Multitaper e
Wavelets. As an{\'a}lises de periodicidades mostraram que esses
eventos s{\~a}o altamente complexos e suas componentes de
freq{\"u}{\^e}ncia s{\~a}o numerosas e vari{\'a}veis de evento
para evento. A an{\'a}lise por wavelets foi a que se mostrou mais
eficiente para an{\'a}lise deste tipo de sinal, e indicou que
flutua{\c{c}}{\~o}es de longo per{\'{\i}}odo de Bz (maiores
que 64 minutos) foram as que resultaram em maior atividade do
{\'{\i}}ndice AE. A an{\'a}lise por multi-resolu{\c{c}}{\~a}o
mostrou que, pela filtragem das altas freq{\"u}{\^e}ncias,
{\'e} poss{\'{\i}}vel obter uma elevada correla{\c{c}}{\~a}o
entre Bz e AE. Na ionosfera auroral, os HILDCAAs foram estudados a
partir de imagens do instrumento UVI, a bordo do sat{\'e}lite
POLAR. Estas imagens de emiss{\~a}o de part{\'{\i}}culas
mostraram pela primeira vez a intensidade e
distribui{\c{c}}{\~a}o da emiss{\~a}o durante estes
fen{\^o}menos. As formas aurorais durante HILDCAAs s{\~a}o
brandas e bem distribu{\'{\i}}das ao longo de toda a oval
auroral e algumas vezes cobrindo toda a calota polar. Foi
investigado se os eventos HILDCAAs eram ou n{\~a}o uma forma
cont{\'{\i}}nua de sub-tempestades. Os resultados mostraram que
a atividade cont{\'{\i}}nua dos eletrojatos aurorais n{\~a}o
correspondem {\`a} sub-tempestades, embora elas possam ocorrer
esporadicamente durante os HILDCAAs. Foi desenvolvido um
m{\'e}todo para quantifica{\c{c}}{\~a}o da emiss{\~a}o auroral
a partir das imagens do POLAR/UVI. Estas medidas, al{\'e}m de
fornecerem a taxa de emiss{\~a}o de part{\'{\i}}culas para
eventos HILDCAAs, mostraram que o efeito integrado desta
emiss{\~a}o ao longo de v{\'a}rios dias pode ser maior do que
durante algumas tempestades geomagn{\'e}ticas intensas. A
an{\'a}lise de el{\'e}trons na faixa de 40-400 KeV mostrou que
durante eventos HILDCAAs ocorre uma inje{\c{c}}{\~a}o
cont{\'{\i}}nua de killer electrons em {\'o}rbitas
pr{\'o}ximas {\`a} Terra (entre L=2 e L=4) por um
per{\'{\i}}odo de v{\'a}rios dias. O efeito integrado destas
inje{\c{c}}{\~o}es de el{\'e}trons pode ser altamente danoso
para equipamentos e sensores embarcados em sat{\'e}lites em
{\'o}rbitas nestas regi{\~o}es, justificando assim a necessidade
de estudos, como o desenvolvido na presente Tese, da variabilidade
do Clima Espacial durante a ocorr{\^e}ncia de eventos HILDCAAs.
ABSTRACT: In this thesis a study about the solar and
interplanetary causes and the geoefective consequences of 14
HILDCAA events occurred between 1998 and 2001 was performed. These
events were chosen by following strictly the selection criteria
for this kind of phenomena. In the interplanetary medium, HILDCAAs
are associated with high speed solar wind streams, wich are
frequently embedded with alfv{\'e}nic fluctuations. At the Sun,
these high speed streams are originated in coronal holes. For each
one of the selected events we have found the most probable coronal
hole from where emanated the high speed stream. Interplanetary
magnetic field and AE index were analyzed to find their
periodicities. Classic techniques, such as power spectrum, and
also modern techniques, as Multitaper and Wavelets, were used.
These analysis show that these events are highly complex and their
frequency components are numerous and variable from one event to
another. The Wavelet analysis is the most favorable technique to
analyze these data. It was found that long period Bz fluctuations
(longer than 64 minutes) resulted in the most significant part of
the AE activity. The Multi- resolution analysis found that,
eliminating the high frequencies in both Bz and AE, a high
correlation can be found between them. In the auroral ionosphere,
HILDCAAs were studied using the UVI instrument onboard POLAR
satellite. These images show, for the first time, the intensity
and distribution of the emission during these events. Auroral
shapes during HILDCAAs were only moderate and well distributed
along the whole auroral oval, and sometimes covering the whole
polar cap. It was investigated whether HILDCAAs are a continuous
form of substorms. The results showed that the continuous activity
observed in auroral electrojects do not correspond to substorm
expansion phases, although some substorms can occur sporadically
during HILDCAAs. A new method was developed to quantify the
auroral emission based in the POLAR/UVI images. These
measurements, besides providing the particle emission rate during
HILDCAAs, showed that the time integrated effect of this emission
during several days can be greater than the values observed during
some intense geomagnetic storms. The electrons in the range
between 40-400 KeV (killer electrons) observed during HILDCAA
events presented continuous injections in orbits close to the
Earth (between L=2 and L=4), lasting for several days. The time
integrated effects of these injections in the geostationary orbits
can be highly harmful to equipments and sensors onboard satellites
orbiting these regions. These effects justify the development of
studies on Space Weather variability during HILDCAA occurrences,
as performed in this Thesis.",
committee = "Sobral, Jos{\'e} Humberto Andrade (presidente) and Alarcon,
Walter Dem{\'e}trio Gonzalez (orientador) and Alves, Maria
Virg{\'{\i}}nia and Alarcon, Al{\'{\i}}cia Luiza Cl{\'u}a de
Gonzalez and Tsurutani, Bruce T. and Ferreira, Jos{\'e}
Leonardo",
copyholder = "SID/SCD",
englishtitle = "A study of the interplanetary and solar origin of high intensity
long duration and continuous auroral activity events",
language = "pt",
pages = "316",
ibi = "6qtX3pFwXQZ3r59YD7/FUaBo",
url = "http://urlib.net/ibi/6qtX3pFwXQZ3r59YD7/FUaBo",
targetfile = "paginadeacesso.html",
urlaccessdate = "20 maio 2024"
}