Electric Field Estimation and Its Relation with X-ray Emission in Large Solar Flares

• Main Authors: Bing-Sian Lin, 林秉賢
• Other Authors: Ya-Hui Yang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/63d9z7

碩士 === 國立中央大學 === 太空科學研究所 === 106 === Solar flares are sudden flash phenomena observed on the solar disk or limb, which are the most powerful energy release event in the solar system. They emit radiation across the entire electromagnetic spectrum, from radio to γ –rays. In the progress of solar flare, electrons are accelerated and move toward to the solar surface along the magnetic field line, bumped into the dense chromosphere and then emit hard X-ray by bremsstrahlung. Because of the temperature gradient, the heated chromospheric plasma rise along the magnetic field line with soft X-ray emission. This study put emphasis on the relation between X-ray emissions and the electric field (one of the particle acceleration mechanisms in solar flare), also other relative parameters. We observe the motion of ribbons with 1600 Å images, then combine the line of sight magnetic field data to calculate the time profile of electric field and other relative parameters. These data are provided by Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) both on Solar Dynamics Observatory (SDO) respectively. On the other hand, according to Neupert effect, we take the time derivative of Soft X-ray flux provided by Geostationary Operational Environmental Satellite (GOES) to stand for hard X-ray flux. By comparing the peak time of hard X-ray and electric field, we found out that electric field peak time prior to that of hard X-ray in most of the events we studied. This indicate close relation between electric field and particle acceleration. Furthermore, high positive correlations between the peak values of several parameters and that of hard X-ray or soft X-ray are found. This also improve our understanding about solar flare properties.