| Texto completo | |
| Autor(es): |
da Costa, Aracy Mendes
;
Domingues, Margarete Oliveira
;
Mendes, Odim
;
Brum, Christiano Garnett Marques
Número total de Autores: 4
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS; v. 73, n. 11-12, p. 14-pg., 2011-07-01. |
| Resumo | |
One way to investigate the magnetosphere-ionosphere coupling is through the simultaneous observation of different parameters measured at different locations of the geospace environment and try to determine some relationships among them. The main objective of this work is to examine how the solar energetic particles and the interplanetary medium conditions may affect the space and time configuration of the ring current at low-latitudes and also to get a better understanding on how these particles interfere with the lower ionosphere in the South Atlantic Magnetic Anomaly region (SAMA). To accomplish this, the cosmic noise absorption (CNA) and the horizontal component of the Earth's magnetic field data measured from sites located in the SAMA region were compared with the proton and electron fluxes, interplanetary medium conditions (solar wind and the north-south component of the interplanetary magnetic field measured on board satellites), the SYM-H index and magnetometer data from Kakioka (KAK-Japan), located significantly outside the SAMA region. The time series analyzed correspond to the geomagnetic disturbance that occurred on August 25-30, 1998. The analysis was performed by implementing wavelet techniques, with particular attention to singularities detection, which highlights the presence of transient signals. The results are discussed in terms of the first three wavelet decomposition levels of the parameters. The magnitude of wavelet coefficients of the solar wind and proton flux at the two energy ranges analyzed is timely well correlated, indicating that these two signals are energetically linked. The larger wavelet coefficient amplitude of KAK and VSS magnetograms shows time delays that are compatible with an asymmetric configuration of the ring current, considering that at the storm time, VSS was at the dawn sector of the magnetosphere and KAK at the dusk side. The wavelet analysis of CNA signals reveals that the signal may be sensitive to the ionization produced by energetic electrons and protons as well. The time delays observed in wavelet coefficients may give an indication of the different accelerating process to which the particles are submitted when traveling along the magnetic field lines, from higher to lower latitudes, and the likely contribution of these particles to the ionization measured as an absorption of the cosmic noise in the lower ionosphere. (C) 2011 Elsevier Ltd. All rights reserved. (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 |