ISTP |
>Admin |
>AGU Spring'97 |
>Abstracts |
*D F Webb (ISR, Boston College, Newton Center, MA 02159, USA; ph. 617-377-3086; e-mail: webb@plh.af.mil); P. McIntosh (Heliosynoptics, Inc.); E. Cliver (AF Research Lab); N. Gopalswamy (Univ. of Maryland); H. Hudson (ISAS)
The magnetic cloud and geomagnetic storm on 10-11 January 1997 was associated with a halo-type CME observed by LASCO near the sun on 6 January. As part of the ISTP and SHINE collaboration on this event we are studying the solar source region of the CME and its propagation through the interplanetary medium to Earth. We summarize the rather weak solar activity that apparently was associated with this CME, and contrast it with the strong surface and coronal activity associated with the 9-11 February 1997 magnetic cloud/storm. We present evidence that the solar sources of both of these events occurred over an area where the southern polar crown filament channel diverted sharply to the north and in the decaying remnants of the first large-scale active region to form during the new solar cycle. Our results also suggest that this region was the site of earlier CMEs; i.e., it was a key site of recurrent activity during 1996-97 which, when aimed toward Earth, produced recurrent magnetic clouds and storms.