Comparison of Concepts and Simulations of the Sub-solar Magnetopause With Measurements

The Polar Satellite experienced more than 1000 sub-solar magnetopause crossings during three spring months in 2001 and 2002. Features of these crossings that both agree with and differ from the static, two-dimensional, picture of the magnetopause will be discussed. In particular, the simple flow of plasma and Poynting flux into the magnetopause in the plus and minus x-directions and out along the plus and minus z-directions will be contrasted with an actual, much more complex, flow. Also, the measured current distributions and power dissipation will be compared with models.