Tuesday, 24 January 2012: 11:45 AM
Unusual and Extensive Equatorial Ionospheric Structures After Reversal of the Drift From Upward to Downward with Applications to Scintillation
Room 252/253 (New Orleans Convention Center )
On occasion, towering plumes are seen to erupt into the F region and eventually push well above the F peak. This can occur well after the reversal of the plasma drift from upward to downward and, after stalling out near 1000 km, they can be over 1000 km across and seem highly turbulent. Curiously, they evolve out of an initial structure on the bottomside, which is only 10 km across. Often, only one such event occurs in an entire evening. In these events, the bottomside at, say, 200 km is usually structured with the same size features, but only one of them erupts. We suggest that one of these seed irregularities was further disrupted by a meteor trail with its associated high electric fields. Intense radar echoes have been associated with meteors in the past. Whatever the origin of these initial channels, they evolve into turbulent features with a volume of 10^10(km)^3. We suggest that once the channel reaches 500 km, it stimulates two-dimensional turbulence that inverse cascades to the huge sizes observed. We predict that these features will cause intense scintillation, even at GPS frequencies.