The NSF GEM Program and the IHY

1. The NSF GEM Program and the IHY R. J. StrangewayIGPP/UCLAGEM Steering Committee Chair

2. Geospace Environment Modeling • Program supported by the National Science Foundation Division of Atmospheric Sciences. • Now in its 14th Year. • Overall goal: development of a Geospace General Circulation Model (GGCM). • GGCM originally envisaged as being a GEM entity. Now GGCMs are more likely to arise out of efforts such as the Boston University Center for Integrated Space weather modeling (CISM). Other examples include the University of Michigan MIURI, and efforts supported by the Community Coordinated Modeling Center (CCMC). • GEM is a forum for providing inputs to the GGCM concept (modules required, science that needs to be addressed to further the GGCM goal).

3. An Earlier GGCM Concept

4. Current Concept of a GGCM • Global MHD provides the spine. • Add-on modules to provide the missing physics. • Example 1: “Knight” relationship that relates current density to parallel potential. Associated energy flux used as input to “Robinson conductivity” to provide enhanced auroral conductivities. • Example 2: Better ionosphere models for lower boundary (TING, TGCM). • Example 3: Pressure gradient and particle drift ring current models. • Future efforts: Sub-scale kinetic/hybrid codes, Data assimilation, better models of the “gap” between the atmosphere and the inner boundary of the MHD code.

5. GEM Elements • Summer workshop is main scientific activity, organized around campaigns. • Student sessions and tutorials important component of GEM summer workshop. • Joint GEM/CEDAR, GEM/SHINE workshops. • Although modeling is the major thrust of GEM, GEM also has a tradition of including ground-based observations, reflecting its NSF support, as well as the intrinsic importance of such observations. • Current workshop size ~ 250 participants – much larger than the number of scientists explicitly supported by GEM grants. • Part of the appeal of GEM is that it still tries to adhere to a workshop mode.

6. GEM Campaigns • 1st Campaign: Boundary layers (1991 - 1998)Mainly emphasized processes at the magnetopause. • 2nd Campaign: Magnetotail/Substorms (1994 - 2004)Largely dominated by substorm issues. • 3rd Campaign: Inner Magnetosphere/Storms (1996 - ??)Campaign Coordinator: M. Liemohn • WG1: Plasmasphere and Ring Current (D. Gallagher, M. Chen) • WG2: Radiation Belts (R. Friedel, R. Thorne) • WG3: ULF Waves (B. Fraser, M. Moldwin)

7. GGCM Science Steering Committee • The GGCM functions within GEM though a science steering committee. • The GGCMSSC works with the campaigns (see later) to identify topics and speakers for each workshop. • The GGCMSSC also acts a liaison with the external computational efforts. • GGCMSSC chair: J. Raeder

8. GEM Campaigns - Continued • 4th Campaign: Magnetosphere-Ionosphere Coupling (1998 - ??)Campaign Coordinators: R. Greenwald, J. Hughes • WG1: Mass Exchange (W. Peterson, R. Winglee) • WG2: Electrodynamic Coupling (W. Lotko, J. Semeter) • WG3 (new): Global Coupling (M. Freeman, D. Murr) • 5th Campaign: Global Interactions (2004 - ??)Campaign Coordinators: T. Phan, D. Sibeck • WG1: Reconnection Dynamics, Cusp, and LLBL (J. Berchem, N. Omidi, K.-H. Trattner) • WG2: Plasma Acceleration and Transport in the Magnetosphere (T. Onsager, A. Otto)

9. What Does GEM bring to IHY? • GEM emphasizes the coupled system. • GEM has international liaison – many of these individuals strongly committed to ground-based observations [X. Blanco-Cano – Mexico; B. Fraser – Australia; E. Donovan – Canada]. Also have Asian and European liaisons. • GEM is actively interested in “Sun to mud” research.

10. What Does IHY bring to GEM? • Sponsorship of a joint GEM/SHINE summer workshop in 2007? • Additional ground networks, especially for developing nations. • Universal processes addressed by GEM science – TO BE DEFINED • Reconnection • Stellar wind - magnetosphere - ionosphere - atmosphere coupling: differential rotation in a magneto-plasma.