Splinter Group - Chairs: P. Reiff (Rice Univ.), D. Lummerzheim (Geophysical Institute, UAF)

Bridging the gap between the magnetosphere and ionosphere. The physical processes that characterise the flow of energy, momentum and mass between the magnetopause and the ionosphere cover a very wide range of scale lengths and time constants. This reality imposes severe constraints on models that attempt to simulate the entire magnetosphere/ionosphere region. This workshop focuses on the physics of the transition region between the lower magnetosphere and the upper ionosphere, with emphasis on particle acceleration mechanisms.

Firstly, we need to review the large body of in situ measurements that have been acquired by ISTP spacecraft. These include phase space distributions of ions and electrons (thermal and energetic), DC and AC electric and magnetic field measurements. How have these data been used to infer field-aligned currents and acceleration mechanisms?

By definition, the transition region is the interface between large scale magnetospheric physics (mostly MHD) and small scale physics described by kinetic and fluid equations. The second topic is, therefore, a brief and concise summary of magnetospheric models that have been developed for ISTP with emphasis on the lower boundary that represents the transition region. Likewise, ionospheric models should briefly be described, with emphasis on the upper boundary assumptions.

The tasks of the workshop are 1) to identify the geophysical parameters that characterise the coupling between regions, 2) to explain the physical processes in the transition region and the models that best describe them, and 3) to highlight observations/measurements that could distinguish between competing physical models and/or yield confirmation, wholly or in part, of a particular model.