Fechar
Metadados

@PhDThesis{Schmitz:2020:MeEnTr,
               author = "Schmitz, Roberta Gon{\c{c}}alves",
                title = "Mecanismos envolvidos em transfer{\^e}ncia de energia em 
                         reconex{\~a}o magn{\'e}tica sim{\'e}trica e assim{\'e}trica 
                         via simula{\c{c}}{\~o}es por part{\'{\i}}culas",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2020",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2020-05-21",
             keywords = "reconex{\~a}o de campo magn{\'e}tico, magnetosfera terrestre, 
                         t{\'e}cnica de part{\'{\i}}cula em c{\'e}lula, plasmas 
                         espaciais, magnetic field reconnection, earth magnetosphere, 
                         particle in cell technique, space plasmas.",
             abstract = "Nesta tese foram tratados alguns cen{\'a}rios poss{\'{\i}}veis 
                         de reconex{\~a}o magn{\'e}tica na magnetosfera terrestre. A 
                         partir dos resultados obtidos usando simula{\c{c}}{\~o}es por 
                         part{\'{\i}}culas com o c{\'o}digo iPIC3D, foram analisadas as 
                         regi{\~o}es de difus{\~a}o dos {\'{\i}}ons e dos 
                         el{\'e}trons, a forma{\c{c}}{\~a}o de frentes de reconex{\~a}o 
                         e os principais mecanismos de convers{\~a}o de energia que 
                         ocorrem na regi{\~a}o de dissipa{\c{c}}{\~a}o e nas frentes de 
                         reconex{\~a}o, bem como a taxa de reconex{\~a}o nos diferentes 
                         cen{\'a}rios. O processo de reconex{\~a}o magn{\'e}tica pode 
                         ser classificado em dois tipos: sim{\'e}trico (RMS) e 
                         assim{\'e}trico (RMA), dependendo das configura{\c{c}}{\~o}es 
                         de campo magn{\'e}tico, densidade, temperatura e velocidade das 
                         part{\'{\i}}culas nos dois regimes de plasma envolvidos. Na 
                         magnetosfera terrestre, a RMS ocorre mais frequentemente na 
                         regi{\~a}o da cauda magn{\'e}tica, onde tanto os campos 
                         magn{\'e}ticos quanto as densidades dos l{\'o}bulos norte e sul 
                         s{\~a}o da mesma ordem de intensidade. Na magnetopausa o processo 
                         mais comum {\'e} a RMA, que ocorre frequentemente quando as 
                         intensidades de campo magn{\'e}tico e/ou densidade da 
                         magnetosfera s{\~a}o significantemente diferentes dos valores da 
                         bainha magn{\'e}tica. RMS e RMA possuem assinaturas 
                         caracter{\'{\i}}sticas e t{\^e}m sido bastante estudadas 
                         atrav{\'e}s de observa{\c{c}}{\~o}es de sat{\'e}lites e de 
                         simula{\c{c}}{\~o}es. Por exemplo, em RMS o campo magn{\'e}tico 
                         perpendicular ao plano de reconex{\~a}o magn{\'e}tica, conhecido 
                         como campo magn{\'e}tico Hall, apresenta um comportamento 
                         quadrupolar devido ao movimento relativo entre os {\'{\i}}ons e 
                         el{\'e}trons. J{\'a} no caso de RMA o campo magn{\'e}tico Hall 
                         possui um aspecto bipolar. Neste trabalho foram apresentados 
                         resultados de simula{\c{c}}{\~o}es de RMS e RMA, com {\^e}nfase 
                         em um caso em particular em que foi encontrado padr{\~a}o 
                         quadrupolar do campo magn{\'e}tico Hall em 
                         observa{\c{c}}{\~o}es de RMA. Nossas simula{\c{c}}{\~o}es 
                         mostraram que as assimetrias presentes n{\~a}o foram suficientes 
                         para apresentar assinaturas de RMA neste caso. A an{\'a}lise de 
                         convers{\~a}o de energia para RMS mostra que a energia 
                         eletromagn{\'e}tica {\'e} em grande parte convertida para 
                         {\'{\i}}ons nas frentes de reconex{\~a}o, o que n{\~a}o 
                         ocorreu no caso RMA, j{\'a} que a convers{\~a}o de energia neste 
                         caso ficou restrita {\`a} regi{\~a}o das separatrizes do lado 
                         que possui campo magn{\'e}tico mais intenso. ABSTRACT: In this 
                         thesis some possible scenarios of magnetic reconnection in the 
                         terrestrial magnetosphere were treated. From the results obtained 
                         using particle simulations with the iPIC3D code, the ion and 
                         electron diffusion regions, the formation of reconnection fronts 
                         (RF) and the main energy conversion mechanisms that occur in the 
                         dissipation region and in the RFs were analyzed, as the 
                         reconnection rate in different scenarios. The magnetic 
                         reconnection process can be classified into two types: symmetric 
                         (SMR) and asymmetric (AMR), depending on the settings of the 
                         magnetic field, density, temperature and velocity of the particles 
                         in the two plasma regimes involved. In the terrestrial 
                         magnetosphere, SMR occurs more frequently in the magnetotail 
                         region, where both the magnetic fields and the densities of the 
                         northern and southern lobes are of the same order of intensity. At 
                         the magnetopause the most common process is AMR, which occurs 
                         quite frequently when the magnitude of magnetic field and/or the 
                         density of the magnetosphere are significantly different than in 
                         the magnetic sheath. SMR and AMR have characteristic signatures 
                         and have been extensively studied through satellite observations 
                         and simulations. For example, in SMR the magnetic field 
                         perpendicular to the plane of magnetic reconnection, known as the 
                         Hall magnetic field, presents a quadrupolar behavior due to the 
                         relative movement between ions and electrons. In the case of ARM, 
                         the Hall magnetic field has a bipolar aspect. In this thesis, 
                         results of SMR and AMR simulations were presented, with emphasis 
                         on a particular case in which a quadrupolar pattern of the Hall 
                         magnetic field was found in AMR observations. Our simulations 
                         showed that the asymmetries we have considered were not enough to 
                         present AMR signatures. The energy conversion analysis for SMR 
                         shows that the electromagnetic energy is largely converted to ions 
                         in the reconnection fronts, which did not occur in the ARM case, 
                         since the energy conversion in this case was restricted to the 
                         separator region on the side that presents more intense magnetic 
                         field.",
            committee = "Dal Lago, Alisson (presidente) and Alves, Maria Virg{\'{\i}}nia 
                         (orientadora) and Souza, Vitor Moura Cardoso e Silva and Batista, 
                         Inez Staciarini and Silveira, Marcos Vinicius Dias and Rojas, 
                         Fl{\'a}via Reis Cardoso",
         englishtitle = "Mechanisms involved in energy transfer in symmetric and asymmetric 
                         magnetic reconnection via particle simulations",
             language = "pt",
                pages = "119",
                  ibi = "8JMKD3MGP3W34R/42E9MNL",
                  url = "http://urlib.net/rep/8JMKD3MGP3W34R/42E9MNL",
           targetfile = "publicacao.pdf",
        urlaccessdate = "05 mar. 2021"
}


Fechar