3D model magneto-acoustic waves in coronal loops observed during transient events

• Ano de defesa: 2017
• Autor(a) principal: Sandra Milena Conde Cuellar
• Orientador(a): Joaquim Eduardo Rezende Costa
• Banca de defesa: Luis Eduardo Antunes Viera, Maria Virgínia Alves, Carlos Guillermo Giménez de Castro, Vera Jatenco Silva Pereira
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Instituto Nacional de Pesquisas Espaciais (INPE)
• Programa de Pós-Graduação: Programa de Pós-Graduação do INPE em Astrofísica
• País: BR
• Link de acesso: http://urlib.net/sid.inpe.br/mtc-m21b/2017/05.05.02.33

We present a three-dimensional analysis of magneto-acoustic waves, along the seven coronal loops, observed on the active region NOAA 11272 during the class B and C flares. We found 19-, 9-, 5-, 2-, 1-, and 0.6-minute waves using the pixelised wavelet filtering method over images obtained from the Atmospheric Imaging Assembly instrument. We modelled the velocity of these waves along the extrapolated magnetic field lines that reproduce the observed loops in extreme ultraviolet. The extrapolation was made over magnetograms, got from the Helioseismic and Magnetic Imager instrument, using the linear force-free approximation. From our model, we found temperatures 10$^{3}$ (maior equivalente) T (menor equivalente) 1.8 x 10$^{7}$ K and densities 10$^{7}$ (maior equivalente) n (menor equivalente) 10$^{17}$ cm$^{−3}$, covering from photosphere to corona, as expected in the solar atmosphere. Hence, we obtained acoustic c$_{s}$ $\approx$ 10$^{2}$ km s$^{−1}$ and Alfvénic $\upsilon$$_{A}$ $\approx$ 10$^{4}$ km s$^{−1}$ velocities values which are in agreement with the literature. In addition, the brightness asymmetry observed along the coronal loops is explained by the magnetic field and Alfvén velocity distributions along the extrapolated field lines. We found fast magneto-acoustic waves at the beginning of B3.8 and C1.9 flares and slow modes along the loops during all flares. Our 3D model represents an unprecedented method to study waves in coronal loops. All results are coherent with expected values in the solar atmosphere conditions.