The full observational assets of the International Solar Terrestrial Physics (ISTP) program have been operational now for slightly over a year. The strategic locations of the ISTP/GGS spacecraft, WIND, GEOTAIL and POLAR, allow fundamental measurements to be obtained on the flow of energy, mass and momentum from the Sun through the heliosphere, into the magnetosphere, with eventual dissipation in the atmosphere. The ISTP/GGS program, together with SOHO, many collaborating spacecraft and ground-based obser vatories, and its theory element has already produced surprising discoveries and demonstrated excellent capabilities for fulfilling its objectives, both for the present as well as for the future. Figure 2-1. For the first time, transient events have been followed from their birth on the Sun, traced through the interplanetary medium, characterized as they near the Earth, and quantified in terms of their geoeffectiveness in creating magnetic storms and accele rating the magnetospheric plasmas. We are beginning to find relationships between solar activity and various transient events in interplanetary space, especially coronal mass ejections (CMEs). In this context, we use the term CME to refer to structures ob served at 1 AU resulting from solar ejecta. We are learning how to track the shocks associated with CMEs and to trace out the spiral structure of the interplanetary magnetic field. We have been able, from in situ measurements within magnetic clouds, to i nfer the connectivity of field lines back to their "birthplace" in the solar active regions. We have observed for the first time the detailed plasma characteristics of the fundamental process of reconnection, especially in the diffusion and ejection regions. We have established the typical location for the elusive nightside reconnection line an d discovered new kinetic effects associated with this. We have followed the gradual input of magnetic flux from the solar wind into the magnetosphere and seen the subsequent bursty conversions of stored energy into heated flowing plasmas in small spatial regions and short time intervals. In these regions we find large electric fields that accelerate particles to high energies. We are answering the important question of the sources of magnetospheric plasma and are understanding how plasma from the ionosphe re can populate the plasma sheet. We are learning how the micro and mesoscale processes of wave-particle interactions play a global role in the birth, transport and loss of charged particles.

New or greatly improved measurement capabilities: New two dimensional directional observations of Type II radio bursts from advancing shocks. Full 3-D measurements of the solar wind distribution functions and energetic particles, including composition. First videos of the ring current evolution during magnetic storms and substorm injections by energetic neutral atom (ENA) imaging. First continuous global observations of aurora simultaneously in visible, ultraviolet and X-ray wavelenghts. The first observations at high altitudes of the outflow of ionospheric ions through the polar magnetosphere. First principles MHD code that simulates the interaction of the incoming solar wind with the magnetosphere and its coupling to the ionosphere