*************************** ** THE GEM MESSENGER ** *************************** Volume 10, Number 1 January 6, 2000 -------------------------------------------------------------------- 1999 GEM Snowmass Workshop Reports Inner Magnetospheres/Storms Campaign WG 1: Plasmasphere/Ring Current -------------------------------------------------------------------- From: Janet Kozyra SUBJECT: GEM Inner Magnetospheres/Storms Campaign REPORT ON: Plasmasphere/Ring Current (WG1) & Joint Workshops GEM99 Snowmass Meeting - June 21-25, 1999 CONVENORS: Janet Kozyra , Jim Horwitz , Geoff Reeves , Larry Lyons , and Jeff Hughes < HUGHES at buasta.bu.edu> The GEM 99 Summer Workshop was the kick off event for the inner magnetosphere/ storms campaign. The purpose of the campaign is to compare and contrast a small number of well-observed magnetic cloud events with the aim of isolating and understanding some of the most pressing science issues involved in the interaction of magnetic clouds with the interplanetary medium, and the response of the terrestrial environment. The goal is to apply information on the inner magnetosphere and its couplings to the solar wind, ionosphere and magnetotail during magnetic storms to the specification of an inner magnetosphere module or modules for the GGCM. SELECTED EVENTS: * 15-18 May 1997 * 24 Sep - 01 Oct 1998 (also an ISTP event study, ISR World Days were 21-25 Sep) * 18-31 October 1998 (ISR World Days were 19-21 Oct) SUMMARY: The Plasmasphere/Ring Current Working Group (WG1) conducted 5 sessions during the GEM meeting last summer either alone or joint with other working groups and campaigns to identify major science issues that might be pursued through comparative analysis of the three storm events listed above. These sessions were: * Introduction and planning for the magnetic storms campaign (joint WG1 & WG2) * Ion outflow and convection (joint session between WG1 and the M-I Coupling Campaign * Global picture of the 3 storm events (joint WG1 & WG2) * Ring current/plasmasphere observations & models for the 3 events (WG1) * Inner magnetosphere / tail coupling issues (joint session among WG1, WG2 and the Tail/Substorm Campaign Major sciences issues identified in these sessions focus on the impacts of high solar wind dynamic pressure on: (1) ion outflow, (2) storm/substorm coupling, (3) global electric field configuration and shielding effects, (4) fate of plasmaspheric material, and (5) ring current sources and losses. A sampling of new results is given below. The POLAR spacecraft was within the polar cap when the dynamic pressure increased dramatically in Sept 98 and provided unique observations of the impacts on the ion outflow. Ion outflows were also observed by LANL geosynchronous satellites during the October 98 event. The auroral oval responded to the enhanced dynamic pressure by immediately brightening uniformly over the dayside oval; the nightside oval followed within 1 minute on Sept 98. Similar behavior was seen during the October 98 event. POLAR EFI observed electric fields down to L~2.2 during the main phase of the Oct 98 storm. SAIDs were seen during both the Sept 98 and Oct 98 events from Millstone Hill radar. Fast flows were seen by MPA at geosynchronous orbit during the Oct 98 event possibly associated with the SAID event at low altitudes. MPA observations show magnetosheath and cold plasmaspheric ions on the same flux tube during both May 97 and Sept 98 raising the possibility of obtaining information on the fate of the plasmaspheric material during high solar wind dynamic pressure events. High solar wind dynamic pressure was due to high densities during the Oct 98 event and high velocities during the Sept 98 event raising the possibility for examining the impacts of these two different conditions on ring current sources and losses. The POLAR spacecraft passed through the ring current peak during the main phase of the Oct 98 storm providing excellent observations of the build up. Interesting signatures of superdense plasma sheets, extreme magnetic field stretching, reverse field draping at dusk, ion outflows, and plasmaspheric drainage were seen at geosynchronous orbit during some or all of these 3 events. NEW ON THE CAMPAIGN WEBSITE A pdf file containing more details on the presentations, contacts and data sources is now available at http://leadbelly.lanl.gov/GEM_Storms/welcome.html. A clearinghouse of observations and model results for these storm events has also been established at this URL. Please email Geoff Reeves with descriptions, contact information, and links to relevant data sets and/or plots for these storm intervals. +-------------------------------------------------------------------------+ |To add name to the mailing list or for a message to the GEM community | | please contact: editor at igpp.ucla.edu | | | |URL of GEM Home Page: http://www-ssc.igpp.ucla.edu/gem/Welcome.html | |Please update your e-mail address. | +-------------------------------------------------------------------------+