@PhDThesis{Pinto:2022:EsDeDe,
author = "Pinto, Ana Clara da Silva",
title = "Estudo da depend{\^e}ncia de decr{\'e}scimos de raios
c{\'o}smicos do tipo Forbush com a rigidez magn{\'e}tica",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2022",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2022-08-16",
keywords = "raios c{\'o}smicos, eje{\c{c}}{\~o}es de massa coronais,
decr{\'e}scimos de Forbush, rigidez geomagn{\'e}tica de corte,
rigidez mediana, cosmic rays, interplanetary coronal mass ejecton,
forbush decrease, geomagnetic cutoff rigidity, median rigidity.",
abstract = "H{\'a} algumas controv{\'e}rsias sobre a depend{\^e}ncia do
tempo de recupera{\c{c}}{\~a}o dos decr{\'e}scimos de Forbush
(Forbush decrease, FD) com a rigidez. Dessa forma, o objetivo
geral deste trabalho {\'e} analisar a depend{\^e}ncia dos FDs
com a rigidez, al{\'e}m de verificar se a depend{\^e}ncia varia
com a invers{\~a}o de polaridade do campo magn{\'e}tico solar
(per{\'{\i}}odo de \≈ 22 anos). Para isso, foram
utilizados 82 detectores de part{\'{\i}}culas, entre monitores
de n{\^e}utrons e detectores de m{\'u}ons da GMDN (Global Muon
detector Network). Ent{\~a}o, 66 ICMEs (Interplanetary Coronal
Mass Ejections) associadas a decr{\'e}scimos de Forbush que
ocorreram entre 1970 e 2018 foram selecionadas. Ademais,
atrav{\'e}s de 4 modelos distintos os seguintes par{\^a}metros
dos FDs foram calculados: a) o tempo caracter{\'{\i}}stico da
fase de recupera{\c{c}}{\~a}o \𝑇\𝑟, definido
como o tempo necess{\'a}rio para que a intensidade se recupere
\≈ 63%; b) a amplitude do decr{\'e}scimo
\𝐼\𝐵\𝑚\𝑖\𝑛, que
{\'e} a diferen{\c{c}}a entre a intensidade na data de
in{\'{\i}}cio da ICME
(\𝐼\𝑏\𝑒\𝑓) e a intensidade
m{\'{\i}}nima registrada durante a passagem da ICME; e c) a
amplitude do FD na fase de recupera{\c{c}}{\~a}o
\𝐼\𝐴\𝑠\𝑟, que {\'a} a
diferen{\c{c}}a entre a intensidade assint{\'o}tica
\𝐼\𝑎\𝑓\𝑡, atingida ap{\'o}s o
fim do efeito da ICME, e a intensidade registrada na data de fim
da passagem da ICME. Calculou-se, por fim, 48254 ajustes, dos
quais 69% deles foram utilizados na an{\'a}lise da
depend{\^e}ncia devido a um processo de exclus{\~a}o de ajustes
fisicamente incompat{\'{\i}}veis. Por fim, conclui-se que: a)
h{\'a} um n{\'u}mero significativo, inclusive majorit{\'a}rio,
de over-recovery do que de eventos em que
\𝐼\𝑎\𝑓\𝑡 =
\𝐼\𝑏\𝑒\𝑓, e um n{\'u}mero
minorit{\'a}rio, por{\'e}m consider{\'a}vel, de under-recovery;
b) as amplitudes
\𝐼\𝐵\𝑚\𝑖\𝑛 e
\𝐼\𝐴\𝑠\𝑟 diminuem com o
aumento da rigidez mediana; c) a depend{\^e}ncia das amplitudes
\𝐼\𝐵\𝑚\𝑖\𝑛 e
\𝐼\𝐴\𝑠\𝑟 com a rigidez de
corte dos n{\^e}utrons {\'e} maior do que a depend{\^e}ncia com
a rigidez de corte dos m{\'u}ons; d) as amplitudes
\𝐼\𝐵\𝑚\𝑖\𝑛 e
\𝐼\𝐴\𝑠\𝑟 diminuem com o
aumento de \𝑃\𝑐 dos n{\^e}utrons e quase
n{\~a}o variam com o aumento de \𝑃\𝑐 dos
m{\'u}ons; e) a prov{\'a}vel depend{\^e}ncia de
\𝑇\𝑟 com a rigidez (\𝑃\𝑚 e
\𝑃\𝑐) ocorre de forma n{\~a}o
sistem{\'a}tica/recorrente, isto {\'e}, diferente para cada
evento; e f) nenhuma das vari{\'a}veis que avaliam a
depend{\^e}ncia dos par{\^a}metros dos decr{\'e}scimos de
Forbush com a rigidez exibiu uma varia{\c{c}}{\~a}o
c{\'{\i}}clica compat{\'{\i}}vel com o ciclo magn{\'e}tico
solar. ABSTRACT: There is a controversy about the dependence of
Fobush decrease's (FD) recovery time with rigidity. Thus, the main
goal of this work is to analyze the FDs dependence with rigidity,
in addition to verify whether the dependence varies with the
polarity inversion of the solar magnetic field (\≈22 -year
period). In orther to do so, 82 cosmic ray detectors were used,
including neutron monitors and muon detectors from the GMDN
(Global Muon detector Network). Then, 66 ICMEs (Interplanetary
Coronal Mass Ejections) associated with Forbush decreases that
occurred between 1970 and 2018 were selected. Furthermore, through
4 different models, the following parameters of the FDs were
calculated: a) the characteristic time of the recovery phase
\𝑇\𝑟, defined as the time needed for the
intensity to recover \≈63%; b) the decrease magnitude
\𝐼\𝐵\𝑚\𝑖\𝑛, which is
the difference between the intensity at the ICME start
\𝐼\𝑏\𝑒\𝑓 and the minimum
intensity recorded during the ICME passage; and c) the FD
amplitude in the recovery phase
\𝐼\𝐴\𝑠\𝑟, which is the
difference between the asymptotic intensity
\𝐼\𝑎\𝑓\𝑡, reached after the
end of the ICME effect, and the intensity recorded at the ICME end
date. Finally, 48254 fits were calculated from which 69% of them
were used in the dependency analysis due to a process of excluding
physically incompatible fits. Lastly, it is concluded that: a)
there is a significant number, the majority of the cases, of
over-recovery as compared to events in which
\𝐼\𝑎\𝑓\𝑡 =
\𝐼\𝑏\𝑒\𝑓, and a smaller
number, but considerable, of under-recovery; b) the amplitudes
\𝐼\𝐵\𝑚\𝑖\𝑛 and
\𝐼\𝐴\𝑠\𝑟 decrease with
increasing median rigidity; c) the dependence of the amplitudes
\𝐼\𝐵\𝑚\𝑖\𝑛 and
\𝐼\𝐴\𝑠\𝑟 with the neutron
cutoff rigidity is greater than the dependence on the muon cutoff
rigidity; d) the amplitudes
\𝐼\𝐵\𝑚\𝑖\𝑛 and
\𝐼\𝐴\𝑠\𝑟 decrease with the
increase of neutrons \𝑃\𝑐 and almost do not vary
with the increase of muon's \𝑃\𝑐 ; e) the
probable dependence of \𝑇\𝑟 with rigidity
(\𝑃\𝑐) occurs in a non-systematic/recurring way,
that is, different for each event; f) none of the variables used
for the dependence analysis of the Forbush decreases with rigidity
exhibited a cyclic variation compatible with the solar magnetic
cycle.",
committee = "Wrasse, Cristiano Max (presidente) and Dal Lago, Alisson
(orientador) and Mendon{\c{c}}a, Rafael Rodrigues Souza de
(orientador) and Silva, Marlos Rockenbach da and Echer, Ezequiel
and Raulin, Jean Pierre and Fauth, Anderson Campos",
englishtitle = "Study of the dependence of cosmic rays decreases of Forbush type
with magnetic rigidity",
language = "pt",
pages = "373",
ibi = "8JMKD3MGP3W34T/47MMH7P",
url = "http://urlib.net/ibi/8JMKD3MGP3W34T/47MMH7P",
targetfile = "publicacao.pdf",
urlaccessdate = "2024, Apr. 29"
}