ausblenden:
Schlagwörter:
-
Zusammenfassung:
We present new analysis of high latitude ionospheric electrodynamics using the high-time resolution (16 s/sec) vector electric field and magnetic field measurements gathered on the Dynamics Explorer-2 satellite. The combined electric and magnetic field data reveal that the high latitude ionosphere electrodynamics is highly structured, typically characterized by large amplitude, narrow “peaks”, and often show very high correlations that are strongest in the cusp. Poynting Flux calculations show values that often exceed 100 mW/m**2, and are considerably higher when the 16 s/sec data are used, compared to values calculated using the 1 s/sec data. Furthermore, we calculate the ratios of E/B and relate this to the integrated Pedersen conductivity. The combined data also reveal numerous examples of large amplitude Alfven waves in the high latitude ionosphere, with amplitudes that are often 100’s of mV/m and 100’s of nT. The waves appear in packets that typically extend for 10-60 seconds along the satellite track (100-500 km horizontal distance), with characteristic wave periods on the order of a second or less. In some cases, the wave amplitudes show evidence of steepening, sometimes revealing well defined, periodic “spikes” within the Alfven wave ensemble. The new analysis of the vector electric field and magnetic field data on DE-2 not only provide a new window on the structured electrodynamics that characterize the high latitude ionosphere, but also reveal important new aspects of energy deposition, field-aligned currents, and coupling between the magnetosphere and ionosphere.
