Title: Magnetic Reconnection and Energy Release in Solar Eruptions

　　Speaker: Jiong Qiu (Montana State University, USA)

　　Time: 10 AM, May 23 (Tuesday）

　　Abstract:
Studying the morphology and photometry of solar flares observed in the lower atmosphere provides measurements of physical quantities characterizing energetics and dynamics of the solar atmosphere. During solar flares, magnetic reconnection takes place in the corona, and the immediate and more significant response to reconnection energy release usually occurs in the lower atmosphere as optical or UV ribbons or kernels. The lower atmosphere is also the only place where reliable measurements of magnetic field are currently available. Therefore, reconnection events in the Sun's corona can be mapped, tracked, and measured with observations of the lower atmosphere during the flare. The chromosphere being the lower boundary of the corona, its radiation signatures provide clues to understanding corona heating. We have developed methods to construct the history of heating, as well as cooling, of numerous flare loops, estimate the amount of energy used in heating these loops, and explore the nature of heating. Magnetic reconnection is also essential in releasing and accelerating coronal mass ejections (CMEs). Furthermore, high-sensitivity chromosphere observations allow us to detect early signatures of CMEs, and trace their evolution from the quasi-equilibrium state to explosive eruption. This talk will report a few new clues we have learned from observations, including the dynamics of flare reconnection, heating of flare plasmas, and CME evolution in the early phase reflected in coronal dimming signatures.