Alfvén waves and Poynting flux observed simultaneously by Polar and FAST in the plasma sheet boundary layer

We present the first simultaneous observations of Alfven waves at Polar and FAST altitudes, ∼7 R E geocentric and ∼3500 km, respectively, at ∼23 MLT in the main phase of a major geomagnetic storm on 22 October 1999. We compare the Poynting flux for these waves and the electron energy flux at the two spacecraft. We also present a new method of Alfven wave analysis, examining Poynting flux magnitude and directionality along with the perturbation electric to magnetic field ratio of these waves as a function of wave temporal scale (frequency). The results of this analysis are compared with those expected from kinetic Alfven wave models. There is a mean net loss of ∼2.1 ergs cm -2 s -1 (mW m -2 ) in earthward Poynting flux over the altitude region between Polar and FAST, a mean net increase in earthward electron energy flux of up to ∼ 1.2 ergs cm -2 s -1 over the same region, frequency characteristics consistent with a mixture of Alfven waves obeying the kinetic Alfven wave dispersion relation mixed with some coupling to the ionosphere, and high-frequency kinetic Alfven wave generation between Polar and FAST. Current models are found to be generally consistent with the study results but are not yet sufficiently well formulated to account for the details, including evidence for temporal and/or spatial modulation of reflectivity.