Atividade solar em comprimentos de onda mm e sub-mm e sua associação com uma ejeção de massa coronal

• Autor(a) principal: Ramírez, Ray Fernando Hidalgo
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do Mackenzie
• Texto Completo: http://dspace.mackenzie.br/handle/10899/24126
• topic: explosão solar em polarização; ejeção de massa coronal; pulsações sub-mm; polarization solar flare; coronal mass ejection; sub-mm pulsations; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS

Solar flares radio emissions provide detailed information on the energy release, particle acceleration, heating processes and plasma conditions at the sites where the radiation is generated. This study focuses in radio emission from millimeter, sub-millimeter and another complementary wavelengths obtained by recent observations that might improve the understanding of processes from the low chromosphere to the corona. Here we study a GOES class X1.7 flare on January 27, 2012 detected by the Solar Sub-millimeter Telescope (SST) at 212 and 405 GHz, and by the solar radio polarimeters (POEMAS) at 45 and 90 GHz. LASCO C2 coronagraph observed a coronal mass ejection (CME) with possible physical connection with phenomena observed at radio-frequencies, including changes in polarization degree (45 and 90 GHz) and enhancements of scintillation index (212 and 405 GHz). The complementary radio observations were obtained by the Radio Solar Telescopes Network (RSTN) at the single frequencies 0.2, 0.4, 0.6, 1.4, 2.7, 4.9, 8.8 and 15.4 GHz and at the 25 - 180 MHz band, and by the Green Bank Solar Radio Burst Spectrometer (GBSRBS) at the 100 - 300 MHz and 300 - 1200 MHz bands. The solar flare exhibits a complex time structure at microwaves consisting of three major enhancements. Type III-like metric and decametric bursts were accompanied by small polarized burst at 45 and 90 GHz with polarization degrees of 0.09 and 0.12, suggesting changes in the magnetic field strength the order of 700 and 2000 G, respectively. SST detected one impulsive burst and significant 10% enhancements of scintillation index intermittently throughout the event. The CME launch time inferred by back extrapolation of the LASCO coronagraph observations to the solar limb coincides approximately in time to the changes in polarization degree, suggesting that CME might be a result of a magnetic transient causing an instability generating the subsequent impulsive structures.