Spatio-temporal entropy analysis of the magnetic field to help magnetic cloud characterization

Autor(es)

Ojeda G, A. ^{[1, 2]} ; Mendes, O. ^[2] ; Calzadilla, M. A. ^[1] ; Domingues, M. O. ^[3]

Afiliação do(s) autor(es)

^[1] Inst Geophys & Astron, Dept Space Geophys, Havana - Cuba

^[2] Natl Inst Space Res, Div Space Geophys, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[3] Natl Inst Space Res, Associate Lab Appl Comp & Math, BR-12227010 Sao Jose Dos Campos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS; v. 118, n. 9, p. 5403-5414, SEP 2013.
• Citações Web of Science: 6

Resumo

The aim of this work is to create a methodology to characterize the dynamics of magnetic clouds (MCs) from signals measured by satellites in the interplanetary medium. We have tested spatio-temporal entropy (STE) technique to study 41 MCs identified by other authors, where the plasma sheath region has been identified. The STE was implemented in Visual Recurrence Analysis software to quantify the order in the recurrence plot. Some tests using synthetic time series were performed to validate the method. In particular, we worked with interplanetary magnetic field (IMF) components B-x, B-y, B-z of 16 s. Time windows from March 1998 to December 2003 for some MCs were selected. We found higher STE values in the sheaths and 0 STE values in some of the three components in most of the MCs (30 among 41 events). The trend is the principal cause of the lower STE values in the MCs. Also, MCs have magnetic field more structured than sheath and quiet solar wind. We have done a test considering the magnetic components of a cylindrically symmetric force-free field constructed analytically, with the result of 0 STE value. It agrees with the physical assumption of finding 0 STE values when studying experimental data in MC periods. The new feature just examined here adds to the usual features, as described in Burlaga et al. (1981), for the characterization of MCs. The STE calculation can be an auxiliary objective tool to identify flux ropes associated with MCs, mainly during events with no available plasma data but only with IMF. (AU)

• Processo FAPESP: 07/07723-7 - Análise das características do acoplamento eletrodinâmico plasma solar-magnetosfera com base nos efeitos das correntes elétricas planetárias
• Beneficiário: Odim Mendes Junior
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• 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