On May 10-12, 1999, preliminary data show that the solar wind density decreased well below 1 / cm**3 for more than a day while the velocity was around 350-400 km/s and the IMF was mostly weakly northward. The magnetic field at geosynchronous orbit showed little of its usual diurnal variation. This unusual interval provides an opportunity to examine solar-terrestrial interactions during a very inflated magnetosphere. Papers are invited that explore the dynamics of the magnetospheric response and recovery; the solar and interplanetary source; the bow shock, magnetosheath and magnetopause; currents, fields and plasmas in the magnetosphere and ionosphere; as well as the comparative analysis of similar unusual events.

Conveners: H. J. Singer, NOAA Space Environment Center, NOAA R/E/SE, 325 Broadway, Boulder, CO 80303, USA, tel: 303-497-6959, fax: 303-497-5388, e-mail: hsinger@sec.noaa.gov; D.B. Berdichevsky, Raytheon-ITSS Corp. at NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA, tel: 301-286-4608, email: berdi@istp1.gsfc.nasa.gov; C. J. Farrugia, Space Science Center, University of New Hampshire, Durham, NH 03824,USA, tel: 603-862-4596, fax: 603-862-0311, e-mail: farrugia@monet.sr.unh.edu; A. J. Lazarus, Center for Space Research, MIT, Cambridge, MA 02139, USA, tel: 617-253-4284, e-mail: ajl@space.mit.edu; T. J. Fuller-Rowell, CIRES/NOAA Space Environment Center, NOAA R/E/SE, 325 Broadway, Boulder, CO 80303, USA, tel: 303-497-6959, fax: 303-497-5764, e-mail: tjfr@sec.noaa.gov