<Objective>
To study the phenomena of magnetoconvection, such as umbral dots and penumbral filaments
<Scientific background>
The fine structures in sunspots, such as umbral dots, penumbral filaments, andlight bridges, are vigorously studied using the SOT data. The origin of these fine structures are known to be the magnetoconvection. Investigating the actual phenomena of the magnetoconvection is highly of interest in the viewpoint of the MHD simulation and physics in the accretion disk and low T stars. Watanabe et al. (2009) suggested the possibility that the oscillatory
convection may occur in umbral dots, which could be clarified by Hinode high cadence, high resolution data. Investigating the proper motion of such phenomena is also important for understanding the interaction between magnetic field and plasma.
We are planning to perform a multiple line scanning of a sunspot with the SST/TRIPPEL. The targets are the center of the umbra (umbral dots) and the boundary of the penumbra (light bridges, penumbral filaments). The Fe I 557.6 nm and Ca IR 854.2 nm are the promising candidates. These lines offers complimentary information between the Hinode, because the Fe I 557.6 nm is suitable for the bisector velocity analysis at the photosphere, and Ca IR 854.2 nm is good for investigating the dynamics of the photosphere to the chromosphere.
Target II. Type II spicules
<Objective>
To find the disk counterpart of type II spicules (De Pontieu et al. 2007).
<Scientific background>
De Pontieu et al. (2007) found two types of spicules; TypeI -spicules by shock waves and Type-II picules by magnetic reconnection. Especially, the type II spicule was newly found by Hinode and the thorough investigation of its properties is in progress now. The study of the type II spicules is important in the viewpoint of transferring the heat to the corona. We want to find the disk counterpart of type II spicules, with collaborative observation at SST/
TRIPPEL spectrograph (Ca II H) and Hinode. We also do spectroscopy above the limb to determine the width of the emission and look for the absorption close to the limb of type II spicules. As the time scale of the spicules is very short (10-150s), very high cadence images is necessary, in addition to the small region scanning by EIS and coronal temperature imaging by XRT. |
|