Observations of magnetic field reconnection at the base of EFR surges

H. kurokawa, Y. Liu, S. Sano, and J. Kiyohara

We found conspicuous Halpha surge activities at the earliest stage of some active regions and suggested that the Halpha surge is one of the first manifestations of the active region birth (Kurokawa 1988). We call such Halpha surges as EFR surges. >From the morphological studies of EFR-surges, we presented a schematic model of surge production where the surge is produced by the reconnection between the emerging magnetic flux and the pre-existing surrounding magnetic field of opposite magnetic polarity (Kurokawa and Kwai 1993). Yokoyama and Shibata (1996) succeeded to reproduce it by their numerical simulation. As for the magnetic field of surge region, we found longitudinal magnetic field flux of an isolated polarity increased at the bases of most surges during and after the surge activities (Sano and Kurokawa 2005). We also found magnetic field cancellation between one polarity of emerging flux and the surrounding opposite polarity at the surge base (Yoshimura et al. 2003, Brooks and Kurokawa 2005). Those observational evidences are all compatible with the reconnection model of the EFR surge. We will challenge to find the first clear evidences of changes in transverse magnetic field at the base of the EFR surges to give proof of the magnetic field reconection with the vector magnetograph of the SOT.

Correspondence

Hiroki Kurokawa (kurokawa@kwasan.kyoto-u.ac.jp), Kwasan & Hida Observatories ,Graduate School of Science, Kyoto University

presentation

oral