Jp. Keady et Ra. Heelis, Regional, scale size, and interplanetary magnetic field variability of magnetic field and ion drift structures in the high-latitude ionosphere, J GEO R-S P, 104(A1), 1999, pp. 199-212
Using data from the Dynamics Explorer 2 satellite's ion drift meter and mag
netometer, we have examined fluctuations in the high-latitude velocity and
magnetic field structure to better understand the coupling between the magn
etosphere and ionosphere. Our study examines perturbations in the frequency
range from 0.25 to 8 Hz, equivalent to static scale sizes between about 30
and 1 km. Seasonal variations in the perturbations at large-scale sizes in
dicate that magnetosphere-ionosphere coupling is dominated by static curren
ts. These static currents display behavior consistent with a current driver
in the auroral zone and a voltage driver in the cusp. In the frequency ran
ge 0.6 to 1.5 Hz the magnetosphere-ionosphere coupling is significantly inf
luenced by Alfven waves with the high-frequency range extending up to 8 Hz
in the cusp.