Solar Physics Division Meeting 2000, June 19-22
Session 1. Helioseismology, Magnetic Fields, Chromosphere and Transition Region
Display, Chair: C. U. Keller, Monday-Thursday, June 19, 2000, 8:00am-6:00pm, Forum Ballroom

[Previous] | [Session 1] | [Next]

[1.53] Magnetic Topology in November 5, 1998 Two-Ribbon Flare as Inferred from Ground-Based Observations and Linear Force-Free Field Modeling

V. B. Yurchyshyn, H. Wang, J. Qiu, P.R. Goode (Big Bear Solar Observatory), V.I. Abramenko (Crimean Astrophysical Observatory)

We analyzed the 3D structure of the linear force-free magnetic field in an active region. A longitudinal magnetogram of AR NOAA 8375 has been used as the photospheric boundary condition. The Nov 5, 1998 2B/M8.4 two-ribbon flare can be explained in the framework of quadrupolar reconnection theory: the interaction of two closed magnetic loops which have a small spatial angle. The energy derived from SXT/YOHKOH data (3 - 6 \times 1030 ergs) is one order of magnitude higher than the lower limit of flare energy predicted by Melrose's model. The latter estimation was made using the linear force-free extrapolation. It is suggested that by taking into account the non-linear character of the observed magnetic field we can increase the lower limit of the magnetic energy stored in the studied magnetic configuration. The revealed magnetic configuration allows us to understand the observed location and evolution of the flare ribbons and the additional energy released during the gradual phase of the flare, as well. Also, the reconnection of closed magnetic loops can logically explain the connection between a two-ribbon flare and the giant X-ray post-flare arch which usually is observed after flare onset. We emphasize that unlike the Kopp and Pneuman configuration, the model discussed here doesn't necessarily need destabilization and opening of the magnetic field.

This work was supported in part by NSF-ATM (97-14796) and NASA (NAG5-4919) grants.

If you would like more information about this abstract, please follow the link to This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract:

[Previous] | [Session 1] | [Next]