Proceedings with Extended Abstracts (single PDF file) - Radio ...

Figure 2: Radar image of coherent E region echoes received over Arecibo at 0039 UT by aportable 30 MHz radar imager deployed on St. Croix.100latitude E layer quasiperiodic (QP) echoes.While QP echoes mainly arrive from patchy,drifting sporadic E layers, they sometimesappear instead to be organized along wavefronts.In Figure 2, a large-scale wave withwavefronts running from northwest to southeastis shown. The wavelength is about 30km, and the period is about 10 min. Animatedsequences of images confirm that thewave propagates to the southwest. Dopplershifts alternate from large positive to negativevalues. These are the line of sight phasespeeds of the small-scale irregularities observedfrom St. Croix. We expect these phasespeeds to be mainly indicative of polarizationelectric fields in the direction normal toboth the radar line of sight and to the geomagneticfield. That is, northeastward andupward or southwestward and downward, approximatelynormal to the wavefronts in Figure2. Overall, the images suggest a largescaleelectrostatic wave moving through theregion.Finally, Figure 3 shows an image ofechoes from the auroral electrojet during atime when rockets launched from the PokerFlat research range were in flight. Each pixelin the image represents a complete DopplerFigure 3: Radar image of auroral E region coherentbackscatter. The “P” and “A” charactersrepresent Poker Flat and Arctic Village,respectively. Anchorage, the site of the radar,is off the bottom edge of the image. The ovalsare the loci of perpendicularity at different Eregion altitudes.