HR: 11:35h
AN: SH52C-06    [Abstracts]
TI: Mangetic field properties at the footpoints of solar microflares (active-region transient brightenings)
AU: * Shimizu, T
EM: shimizu.toshifumi@isas.jaxa.jp
AF: ISAS/JAXA, 3-1-1 Yoshinodai, Sagamihara, Kanagawa, 229-8510, Japan
AU: Kano, R
EM: ryouhei.kano@nao.ac.jp
AF: NAOJ, Mitaka, Tokyo, 181-8588, Japan
AU: Katsukawa, Y
EM: yukio.katsukawa@nao.ac.jp
AF: NAOJ, Mitaka, Tokyo, 181-8588, Japan
AU: Kubo, M
EM: kubo@ucar.edu
AF: HAO/NCAR, P.O.Bpx 3000, Boulder, CO 80307, United States
AU: DeLuca, E
EM: edeluca@cfa.harvard.edu
AF: SAO, 60 Garden St., Cambridge, MA 02138, United States
AU: Ichimoto, K
EM: ichimoto@solar.mtk.nao.ac.jp
AF: NAOJ, Mitaka, Tokyo, 181-8588, Japan
AU: Lites, B
EM: lites@ucar.edu
AF: HAO/NCAR, P.O.Bpx 3000, Boulder, CO 80307, United States
AU: Nagata, S
EM: nagata@kwasan.kyoto-u.ac.jp
AF: Kyoto University, Takayama, Gifu, 506-1314, Japan
AU: Sakao, T
EM: sakao.taro@isas.jaxa.jp
AF: ISAS/JAXA, 3-1-1 Yoshinodai, Sagamihara, Kanagawa, 229-8510, Japan
AU: Shine, R
EM: shine@lmsal.com
AF: LMSAL, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304, United States
AU: Suematsu, Y
EM: suematsu@solar.mtk.nao.ac.jp
AF: NAOJ, Mitaka, Tokyo, 181-8588, Japan
AU: Tarbell, T
EM: tarbell@lmsal.com
AF: LMSAL, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304, United States
AU: Title, A
EM: title@lmsal.com
AF: LMSAL, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304, United States
AU: Tsuneta, S
EM: saku.tsuneta@nao.ac.jp
AF: NAOJ, Mitaka, Tokyo, 181-8588, Japan
AB: Solar active regions produce numerous numbers of small-scale explosive energy releases, i.e., microflares, which are captured by imaging observations in soft X-rays as transient brightenings of small-scale coronal loops. Thanks to advanced performance of X-Ray Telescope (XRT) onboard the Hinode satellite, we can investigate finer structure of the brightening X-ray sources in more details than we did with Yohkoh data. One of important questions on microflares is what causes microflares. The simultaneous visible-light observations by the Solar Optical Telescope (SOT) allow us to explore magnetic activities and magnetic field configuration at the photospheric footpoints of brightening loops, giving key observations to investigate the question. For our investigations of corona-photosphere magnetic coupling, we have established co-alignment between SOT and XRT with accuracy better than 1 arcsec (Shimizu et al. 2007, PASJ in press). It turns out that Ca II H observations are very useful to identify the exact positions of footpoints of X-ray transient brightening loops. Small "Kernels" are sometimes observed in Ca II H and they may be signature of highly accelerated non-thermal particles impinging on chromosphere. As already shown in Shimizu et al.(2002), frequent transient brightenings are observed at the locations where emerging activities are on going. However, another type of brightening triggering mechanism should exist to explain some observed multiple-loop brightenings. In the multiple-loop brightenings, multiple loops are magnetically in parallel with each other and no apparent magnetic activities, such as emerging and canceling, are observed at and near the footpoints. This paper will present SOT observations of some microflares observed with XRT.
DE: 7507 Chromosphere
DE: 7509 Corona
DE: 7524 Magnetic fields
DE: 7529 Photosphere
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting