Bidimensional hidrodinamic model of coronal mass ejections / Modelo hidrodinâmico bidimensional de ejeção de massa coronal

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

A twodimensional hydrodynamical model is used to follow, in time and space, coronal structures that propagate through the interplanetary medium. These estructures are known as Coronal Mass Ejections (CMEs). A twodimensional grid with the steady state solar wind solution representing the inteplanetary medium is used as the initial condition. The steady state solar wind solution is obtained using a numerical code where the fluid parameters density, speed and temperature are varied in a way that will represent the condition of the solar wind that the problem demands (maximum or minimum of solar cycle). The boundary conditions are set as fixed at the position where the Sun is located and are set as free in the rest of the boundary points. A numerical hydrodynamical code is created based in a method called Modified LaxWendroff (MLW), where a pulse of density or temperature or speed, or even a combination of those, is introduced to simulate a perturbation in the medium, that is, a CME. The system was iterated in time and space. The speed and morphology of the CMEs were found to be in good agreement with the LASCO observational data, for a grid with the same size as the LASCO field of view, around 20 R⊙. The morphology of the CMEs was fully reproduced with this code. A grid with 160x250 R⊙ was created and a pulse was added in the same way as with the small grid. The new system was iterated and the arrival time of the CME close to the Earth s orbit was calculated. The morphology, speed, expansion angle and arrival time obtained for the simulated CMEs, for both grids, show a good correlation with the observacional data, for example, from LASCO.

ASSUNTO(S)

coronal mass ejections simulação direta numérica magnetosfera da terra coroa solar direct numerical simulation ejeção de massa coronal sun earth magnetosphere sol solar corona

ACESSO AO ARTIGO

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