경희대학교 BK21

 

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● 날짜 : 2016년 09월 02일 (금요일)
● 시간 : 14시 00분
● 장소 : 천문대 영상실
● 강사 : Prof. Stephane Regnier (Northumbria University, Newcastle Upon Tyne, UK)
 
Title : Heating and Cooling of Multi-stranded Coronal Loops
 
Abstract :
Solar coronal loops are often observed in active regions at a variety of wavelengths, especially in the Extreme Ultra-Violet (EUV) range. Since 2010, coronal loops are scrutinized in different EUV channels by the Atmospheric Imager Assembly (AIA) on board the Solar Dynamics Observatory (SDO), which strongly indicates that the observed coronal plasma along loops is multi-thermal and contains fine structures. Based on this observation, we model coronal loops as a collection of fine strands satisfying the hydrodynamics equations. From this 1D hydrodynamic model, we study the heating and cooling processes within a coronal loop defined as an assemble of fine strands. The multi-thermal nature of the heated multi-stranded loops is evidenced in spectroscopic observations, especially in the distribution of Dopplershifts covering spectral lines from the chromosphere to the hot corona. A new temperature diagnostic for heated loops is provided. In addition, the cooling of modelled coronal loops is compared to simulated observations for the SDO/AIA instrument. This study also leads to a new temperature diagnostic of coronal loops, including the cooling profile. The use of these temperature diagnostics for new and forthcoming solar missions (IRIS, Solar Orbiter/SPICE) is also discussed. finally, we compare the behaviour of the loops subject to different heating frequency, from low-frequency heating to high frequency heating. We discuss the implications in terms of possible observations and new instrumentation.