Systematic variation in observing altitude of enhanced ion line by the pump near fifth gyroharmonic
The observation of ultra high frequency radar during an ionospheric experiment carrying out at the European Incoherent Scatter Scientific Association, demonstrates a systematic variation in the altitude of the pump enhanced ion line, which is quite remarkably dependent on the pump frequency, that is, when the pump frequency sweeps above the fifth gyroharmonic, the altitude of the enhanced ion line is ~3 to ~6 km lower than that at the pump frequency very close to the fifth gyroharmonic. The analysis shows that the systematic variation in the altitude of the pump enhanced ion line is principally dependent on the enhanced electron temperature, although the changes in the profile of the electron density brought about by the ionospheric heating are not independent of those systematic altitude variations.
This is a peer-reviewed, un-copyedited version of an article published in Plasma Science and Technology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/2058-6272/aadd44.