During the period of the event, WIND measured a solar plasma speed of
310-320 km/s and very quiet IMF conditions. The component was
within 2 nT of zero and mainly negative from 15:00 to 17:00 UT.
IMP8 data were not available.
The
index at the time of the event was 1.0 and rising.
The morphology map of Figure 5.16 shows a moderate amount
of backscatter.
Clearly visible is an area of missing backscatter from E to
E and
N to
N latitude for both radars.
Just beyond that region at higher latitudes double-peaks can be found
in the spectrum, forming a banded region centered around
N. Both
radars observe the spectral features.
Figure 5.16: Map of spectral findings from the Saskatoon and Kapuskasing radars: 1 Jan/95
As indicated in Figure 5.17, the satellite passes through
the region where
spectral features can be seen from -
and through the
blank region where the radars do not detect echoes from
-
.
Figure 5.17: Peak-map with overlaid flight path of the DMSP F12 satellite: 1
Jan/95
The energy and fluxes shown in Figure 5.18 correlate with
the radar measurements of the double peaked spectra.
The flux increases past a value of at
while average energies are at or below
and quite variable.
There is a sharp increase in both the flux and characteristic energy at
, after which
the average electron energy remains steady at about
. The flux then
drops below
at
while the characteristic
energy remains at about
until the satellite leaves the field of
view of the radars.
Figure 5.18: Average electron energy and flux determined from SSJ/4 instrument
measurements: 1 Jan/95
Figure 5.19 shows, as expected, a high F-layer ionization rate
when there was a large flux of soft electrons with characteristic energy
around .
This interval corresponds exactly with the
occurrence of the double-peaked spectra from
to
. Similarly, the high energy fluxes measured later produce a high
ionization in the E-layer from
to
, corresponding to the
region of missing backscatter in the radar data.
Figure 5.19: Estimated ionization rates at E- and F-layer heights determined from electron
spectra measurements: 1 Jan/95
Figure 5.20 shows a sharp conductivity increase
starting at . If the satellite speed is taken as
, the
sharp increase in the Pedersen conductivity corresponds to a conductivity
gradient along the satellite track of
,
centered at
.
Figure 5.20: Estimated E-layer conductivities from the Robinson model: 1 Jan/95
The velocity map for the event, as shown in Figure 5.21,
indicates a
relatively steady flow northward of the region where double-peaked spectra were found.
In the region around E and
N the flow vectors are of low velocity
and variable in direction. This quasi-turbulent behaviour of the velocity
vectors is consistent with the assumption that the double-peaks are caused
by Kelvin-Helmholtz instability driven turbulence.
Figure 5.21: SuperDARN velocity map: 1 Jan/95