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6 Jan/95, 17:03 - 17:05 UT

During the event, WIND measured a solar plasma speed of around 600 km/s. The IMF conditions were such that the tex2html_wrap_inline5386 component shifted from negative to positive around 16:00 UT while the tex2html_wrap_inline4540 component remained positive throughout the period. IMP8 data were not available. The tex2html_wrap_inline4548 index at the time of the event was 2.5.

In the overview of Figure 5.22 a large section of the backscatter region shows double-peaked spectral features. Both radars observe the features in approximately the same region, although the Saskatoon radar finds more of them. Distinguishable is also a segmentation into two bands of double-peaked spectral events with single peaked spectra between these regions along a line from tex2html_wrap_inline5392 E and tex2html_wrap_inline5394 N to tex2html_wrap_inline5396 E and tex2html_wrap_inline5326 N. Also visible is a patch of missing radar scatter, centered around tex2html_wrap_inline5400 E and tex2html_wrap_inline5402 N. This region is very much larger for the Kapuskasing radar than for the Saskatoon radar, indicating that either the scattering conditions or the propagation conditions were less favourable for the Kapuskasing radar.

Figure 5.22: Map of spectral findings from the Saskatoon and Kapuskasing radars: 6 Jan/95

The satellite flight path goes first through the regions with double-peaked spectra from tex2html_wrap_inline5404 - tex2html_wrap_inline5406 and from tex2html_wrap_inline5408 - tex2html_wrap_inline5410 , skims the area of missing backscatter around tex2html_wrap_inline5412 and then enters a zone of normal backscatter and spectra (see Figure 5.22 and 5.23).

Figure 5.23: Peak-map with overlaid flight path of the DMSP F12 satellite: 6 Jan/95

Figure 5.24 shows a zone of variable flux at low energies from tex2html_wrap_inline5414 to tex2html_wrap_inline5416 followed by a zone of steady flux with high electron energies of tex2html_wrap_inline5418 (after tex2html_wrap_inline5420 ). Interesting is a peak of almost tex2html_wrap_inline5422 in the characteristic energy at tex2html_wrap_inline5424 with a severe dropout in the flux. This is in a region of several maxima in the flux and highlights the highly variable flux conditions in this segment.

Figure 5.24: Average electron energy and flux determined from SSJ/4 instrument measurements: 6 Jan/95

The ionization rates in Figure 5.25 match the spectral findings and the low-energy and high-flux regions. A region of increased F-layer ionization can be identified from about tex2html_wrap_inline5414 to tex2html_wrap_inline5410 and from tex2html_wrap_inline5412 to tex2html_wrap_inline5432 , which corresponds to the regions of low energy precipitation and double-peaked spectra. The ionization is very variable, and the flux peaks are short in duration, often only 5 - tex2html_wrap_inline5436 , which corresponds to spatial structures only about 35 - tex2html_wrap_inline5440 in width or diameter. The results suggest a spatially inhomogeneous region populated with columns which are like large-scale auroral rays, except that the columns are associated with large fluxes of less than 1 keV electrons. It is conceivable that these structures can produce the banded regions described earlier. At tex2html_wrap_inline5416 and later one can observe a region of high E-layer ionization.

Figure 5.25: Estimated ionization rates at E- and F-layer heights determined from electron spectra measurements: 6 Jan/95

The region of E-layer ionization shows up very well in Figure 5.26 in the E-layer conductivities. Remarkable though is a peak at tex2html_wrap_inline5412 of 40 mhos coinciding exactly with the location of the beginning of missing backscatter; the gradient reaches here a magnitude of tex2html_wrap_inline5448 over a very short spatial region of only about tex2html_wrap_inline5450 along the satellite track, which is the distance traversed in about tex2html_wrap_inline5452 .

Figure 5.26: Estimated E-layer conductivities from the Robinson model: 6 Jan/95

As can be seen in Figure 5.27, double-peaked spectra occur in a region of steady northward flow at velocities ranging from tex2html_wrap_inline5454 to tex2html_wrap_inline5456 .

Figure 5.27: SuperDARN velocity map: 6 Jan/95

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Next: 16 Jan/9516:45 - Up: Morphology during a Complete Previous: 1 Jan/9516:21 -

Andreas Schiffler
Wed Oct 9 10:05:17 CST 1996