Interplanetary medium condition effects in the South Atlantic Magnetic Anomaly: A case study |
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| Authors: | Aracy Mendes da Costa Margarete Oliveira Domingues Odim Mendes Christiano Garnett Marques Brum |
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| Institution: | 1. Instituto Nacional de Pesquisas Espaciais (INPE), 12227-010, São José dos Campos, São Paulo, Brazil;2. Divisão de Geofísica Espacial, CEA/INPE, Brazil;3. Laboratório Associado de Computação e Matemática Aplicada (LAC), CTE/INPE, Brazil;4. National Astronomy and Ionosphere Center, Space and Atmospheric Science Department, Arecibo Observatory, Puerto Rico, USA;1. Arecibo Observatory, SRI International, HC-3 Box 53995, Arecibo, PR 00612, USA;2. Cooperative Institute for Research in Environmental Sciences & Department of Aerospace Engineering Sciences, University of Colorado at Boulder, 216 UCB, Boulder, CO 80309, USA;3. Puerto Rico Photonics Institute, Universidad Metropolitana, San Juan, PR 00926, USA;1. Indian Centre for Space Physics, 43 Chalantika, Garia St. Road, Kolkata 700084, India;2. S.N. Bose National Centre for Basic Sciences, JD Block, Sector-III, Salt Lake, Kolkata 700098, India;3. University of Electro-Communication, 1-5-1 Chofugaoka, Chofu, Tokyo, Japan;1. School of Chemistry, University of Leeds, Leeds LS2 9JT, UK;2. NCAS, School of Earth and Environment, University of Leeds, Leeds, UK;1. Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008;2. Key Laboratory of Space Object and Debris Observation, Chinese Academy of Sciences, Nanjing 210008;3. State Key Laboratory of Astronautic Dynamics, Xi’an Satellite Control Center, Xi’an 710043;1. Professor of Allameh Tabatabai University, Tehran, Tehran, Iran;2. Islamic Azad University, Roudehen Branch, Young Researchers Club, Tehran, Iran;1. Institute of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing 211101, China;2. State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China;3. State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100190, China |
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| Abstract: | 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. |
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