The proposed GGS/SOLARMAX program is a fundamental component of a NASA’s Sun-Earth Connection program. The importance of GGS/SOLARMAX to the program is illustrated with Figure 3.1, which represents schematically the flow of energy from the Sun thro ugh geospace. The major components of the Sun-Earth connected system – interplanetary space, the regions of the magnetosphere, the ionosphere and the atmosphere represented as blocks – can be compared to cellular structures connected by thin boundary laye rs, illustrated as arrows. The bulk of the mass, momentum and energy of the system resides within the large-volume cells that play different roles in the transport, storage and evolution of these quantities within the system. The study of the system requi res an ability to investigate not only the processes by which these quantities reside within and evolve through the large-volume cells, but also the physics of the boundary layers and the coupling mechanisms. Figure 3.1. Current research in Sun-Earth connections includes several specialized missions, IMP-8, FAST, and SAMPEX, plus the LANL and GOES geosynchronous spacecraft and non-GGS ground based facilities. These spacecraft and facilities are highly complementary to th e ISTP/GGS constellation in their functions and objectives. These missions are placed in Figure 3.1 to illustrate their contributions to the overall understanding of the Sun-Earth system. Several other similarly specialized missions will soon be launched, including Equator-S and ACE this year and IMAGE and CLUSTER in the year 2000. Equator-S and IMAGE will make major contributions to the study of the interior of the magnetosphere, highly complementing GGS/SOLARMAX. However, these specialized missions alon e can only provide a very limited understanding of the global flow of mass, energy and momentum through the geospace system, the interrelationships between the cells of the system, and the determination of the extremes of the system during solar maximum. The roles of GEOTAIL, WIND and POLAR in the study of the Sun-Earth connected system are also illustrated schematically in Figure 3.1 (in red). Note that among the current programs, the GGS spacecraft provide the only observations of the coupling of the so lar wind into the parts of the magnetosphere and play the dominant role in the observation of coupling through the polar auroral magnetosphere and the geomagnetic tail. Not shown in the diagram are theoretical investigations that provide a global unifica tion to the widely spaced experimental observations with the development of simulation and predictive models, precursors to the envisioned operational models in the National Space Weather effort. The value of GGS/SOLARMAX has been recognized by the Sun-Ea rth Connection science roadmap team which endorsed continuation of GGS through solar maximum as a cornerstone of the NASA strategic plan. This diagram clearly illustrates that GGS/SOLARMAX facilities play a key role in the Sun-Earth Connection Program.

Comparison of Magnetic Storms Solar minimum: Solar energetic particles: a few weak events. Energetic trapped electrons: enhanced to high intensities. Ring current: small to moderate; lack of oxygen ions. Particle precipitation: in nominal auroral oval. Ionospheric source for plasma sheet: minimum contribution. Great storms of solar maximum: Solar energetic particles: large events, potentially dangerous to humans in space. Energetic trapped electrons: extreme enhancements. Ring current: intense to low L values; oxygen dominated. Particle precipitation: intense, wide oval; low latitude aurora; sea level cosmic rays. Ionospheric source for plasma sheet: important oxygen contribution. Figure 3.2