Space physics and aeronomy
Manuscript - Ionospheric heating experiment with HF frequency-sweeping -- original radar power dataThis is the original data from the UHF diagnostic radar at HAARP during the experiment. The data represent the total back-scattered power (as function of time) from the Langmuir Parametric Decay Instability that occurs at a height immediately below the HF cut-off height that corresponds to the frequency of the high-power HF wave from the HAARP facility.
Manuscript - Ionospheric heating experiment with HF frequency-sweeping -- supplemental TEC dataThis TEC data includes the altitude of the TEC measurements inside the HAARP beam. The TEC data were acquired using an oblique ray path through the HAARP beam.
High-speed observation of sprite streamersSprites are optical emissions in the mesosphere mainly at altitudes 50–90 km. They are caused by the sudden re-distribution of charge due to lightning in the troposphere which can produce electric fields in the mesosphere in excess of the local breakdown field. The resulting optical displays can be spectacular and this has led to research into the physics and chemistry involved. Imaging at faster than 5,000 frames per second has revealed streamer discharges to be an important and very dynamic part of sprites, and this paper will review high-speed observations of sprite streamers. Streamers are initiated in the 65–85 km altitude range and observed to propagate both down and up at velocities normally in the 106–5 9 107 m/s range. Sprite streamer heads are small, typically less than a few hundreds of meters, but very bright and appear in images much like stars with signals up to that expected of a magnitude -6 star. Many details of streamer formation have been modeled and successfully compared with observations. Streamers frequently split into multiple sub-streamers. The splitting is very fast. To resolve details will require framing rates higher than the maximum 32,000 fps used so far. Sprite streamers are similar to streamers observed in the laboratory and, although many features appear to obey simple scaling laws, recent work indicates that there are limits to the scaling.