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Next: Discussion Up: Morphology during a Complete Previous: 21 Feb/952:30 -

25 Feb/95, 1:42 - 1:44 UT

This is event is characterized by a low solar wind speed of 275 km/s, a small positive tex2html_wrap_inline4540 and only slight sign changes in the tex2html_wrap_inline5474 component of the IMF during the period. IMP8 is located in the tail region. The tex2html_wrap_inline4548 index at the time of the event was below 1.0.

A large area of backscatter has been recorded during this event from both radars. Visible in Figure 5.64 are three distinct regions of double-peak spectra occurrences. One patch is centered at about tex2html_wrap_inline5512 E and tex2html_wrap_inline5680 N, an extended band stretches from tex2html_wrap_inline5392 E and tex2html_wrap_inline5796 N in a curve southeast to tex2html_wrap_inline5798 E and tex2html_wrap_inline5708 N and a patch is located further south, centered at about tex2html_wrap_inline5802 E and tex2html_wrap_inline5510 N.

Figure 5.64: Map of spectral findings from the Saskatoon and Kapuskasing radars: 25 Feb/95

As can be seen in Figure 5.65, the track of the satellite is situated very well for observations. It enters the south-east patch of double-peaked spectra at about tex2html_wrap_inline5806 , exits at about tex2html_wrap_inline5808 and reenters the extended band at tex2html_wrap_inline5810 , leaving at tex2html_wrap_inline5812 .

Figure 5.65: Peak-map with overlaid flight path of the DMSP F12 satellite: 25 Feb/95

Figure 5.66: Average electron energy and flux determined from SSJ/4 instrument measurements: 25 Feb/95

It is apparent from Figure 5.66 that both periods include satellite observations of increased flux. The low energy precipitation begins at about tex2html_wrap_inline5814 with a sharp peak. The features are more apparent in Figure 5.67 where it can be seen that F-layer ionization is high from about tex2html_wrap_inline5806 to tex2html_wrap_inline5818 and again from tex2html_wrap_inline5820 to tex2html_wrap_inline5822 . Both periods correspond to regions of double-peaked spectra seen with the radar.

Figure 5.67: Estimated ionization rates at E- and F-layer heights determined from electron spectra measurements: 25 Feb/95

The conductance graphs of Figure 5.68 show little E-layer conductance changes.

Figure 5.68: Estimated E-layer conductivities from the Robinson model: 25 Feb/95

The velocity map of Figure 5.69 is characterized by low velocities and complex convection patterns. The regions of double-peaked spectra are present in all areas of the flow map and do not seem to correspond to a particular region.

Figure 5.69: SuperDARN velocity map: 25 Feb/95

next up previous
Next: Discussion Up: Morphology during a Complete Previous: 21 Feb/952:30 -

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