[PEM17-24] Determination of 3D velocity fields of disappearing and erupting solar filaments using SMART/SDDI at Hida observatory
キーワード：宇宙天気、フィラメント消失、フィラメント噴出
Solar flares, explosions on the solar surface, and associated eruptive phenomena affect the interplanetary environment, space weather, and these sometimes cause various damages on our infrastructures. Therefore, it is becoming more and more important to forecast space weather. Filament eruptions, eruptions of cool and plasmas floating in the solar corona into the interplanetary space, highly related to coronal mass ejections, and therefore, they are thought to be one of the sources of magnetic storms. However, the relation among filament eruptions, coronal mass ejections, and magnetic storms has not yet been clarified well. One of the reasons for this is the lack of accurate measurements of the velocity field of filaments and the temporal evolution. We have not been able to determine precisely whether the plasma is actually ejected into the interplanetary space. It is impossible to obtain the line of the sight velocity field of the filament plasma only by the H-alpha line center (6562.808 Angstrom) image.
The SDDI (Solar Dynamics Doppler Imager) installed in SMART (Solar Magnetic Activity Research Telescope) in Hida observatory can take the solar chromospheric full-disk dataset with 0.25 Angstrom step between -9 to +9 Angstrom centered at H-alpha line. This means that we can get a spectrum of the H-alpha line for the entire region of the filament. In this study, by applying the Beckers's “cloud model” to the filament observation at 73 wavelengths, we can detect the line of sight velocity up to 400km/s.
We calculated the line of sight velocities of the filament eruption which started at 23:30UT on 2016 August 9. The filament is located at the north east limb of the sun, and ejected to become a CME. We tracked the three-dimensional morphological changes of the filament structure entirely from the pre-ejection stage to the disappearance by checking the dense part in H-alpha and AIA images by eyes. We also confirmed the magnetic structure of the erupted filament by using a magnetogram taken with Solar Dynamic Observatory (SDO) /Helioseismic and Magnetic Imager (HMI). We also compared the activities of filament eruption and CME from the aspect of the time variation of the speed and direction to obtain the detailed evolution of the filament eruption which is useful for the space weather forecast.
The SDDI (Solar Dynamics Doppler Imager) installed in SMART (Solar Magnetic Activity Research Telescope) in Hida observatory can take the solar chromospheric full-disk dataset with 0.25 Angstrom step between -9 to +9 Angstrom centered at H-alpha line. This means that we can get a spectrum of the H-alpha line for the entire region of the filament. In this study, by applying the Beckers's “cloud model” to the filament observation at 73 wavelengths, we can detect the line of sight velocity up to 400km/s.
We calculated the line of sight velocities of the filament eruption which started at 23:30UT on 2016 August 9. The filament is located at the north east limb of the sun, and ejected to become a CME. We tracked the three-dimensional morphological changes of the filament structure entirely from the pre-ejection stage to the disappearance by checking the dense part in H-alpha and AIA images by eyes. We also confirmed the magnetic structure of the erupted filament by using a magnetogram taken with Solar Dynamic Observatory (SDO) /Helioseismic and Magnetic Imager (HMI). We also compared the activities of filament eruption and CME from the aspect of the time variation of the speed and direction to obtain the detailed evolution of the filament eruption which is useful for the space weather forecast.