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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Daubechies wavelet coefficients: a tool to study interplanetary magnetic field fluctuations

Texto completo
Autor(es):
Gonzalez, Arian Ojeda [1, 2] ; Mendes Junior, Odim [2] ; Domingues, Margarete Oliveira [3] ; Menconi, Varlei Everton [2]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Inst Geophys & Astron, Dept Space Geophys, Havana - Cuba
[2] Natl Inst Space Res INPE, DGE CEA, BR-12227010 Sao Jose Dos Campos, SP - Brazil
[3] Natl Inst Space Res INPE, LAC CTE, BR-12227010 Sao Jose Dos Campos, SP - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: GEOFISICA INTERNACIONAL; v. 53, n. 2, p. 101-115, APR-JUN 2014.
Citações Web of Science: 5
Resumo

We have studied a set of 41 magnetic clouds (MCs) measured by the ACE spacecraft, using the discrete orthogonal wavelet transform (Daubechies wavelet of order two) in three regions: Pre-MC (plasma sheath), MC and Post-MC. We have used data from the IMF GSM-components with time resolution of 16 s. The mathematical property chosen was the statistical mean of the wavelet coefficients ({Dd1}). The Daubechies wavelet coefficients have been used because they represent the local regularity present in the signal being studied. The results reproduced the well-known fact that the dynamics of the sheath region is more than that of the MC region. This technique could be useful to help a specialist to find events boundaries when working with IMF datasets, i.e., a best form to visualize the data. The wavelet coefficients have the advantage of helping to find some shocks that are not easy to see in the IMF data by simple visual inspection. We can learn that fluctuations are not low in all MCs, in some cases waves can penetrate from the sheath to the MC. This methodology has not yet been tested to identify some specific fluctuation patterns at IMF for any other geoeffective interplanetary events, such as Co-rotating Interaction Regions (CIRs), Heliospheric Current Sheet (HCS) or ICMEs without MC signatures. In our opinion, as is the first time that this technique is applied to the IMF data with this purpose, the presentation of this approach for the Space Physics Community is one of the contributions of this work. (AU)

Processo FAPESP: 08/09736-1 - Estruturação de um ambiente computacional científico para análise de eventos complexos do acoplamento eletrodinâmico Sol-Terra
Beneficiário:Varlei Everton Menconi
Modalidade de apoio: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico