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Ionosphere irregularity mathematical models from satellite radio sounding data of heights below F 2 maximum
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kotonaeva, Nadia Fedorov |
| Copyright Year | 2005 |
| Abstract | First results of ionosphere irregularity mathematical models analysis for topside sounding below F2 maximum are reported. The sounding was accomplished from onboard of Russian MIR manned space station where topside sounder was installed. New phenomenon on ionogram is continuation of a trace of reflection from the Earth, which on the low-frequency end does turn almost on 180 degrees and proceeds with increases in frequencies almost up to the end of a frequency range. Never earlier in all experiments with topside sounding an ionosphere of anything similar it was observed. This trace has received the name related lower trace (RLT). For understanding of essence of the new phenomenon and finding-out of utility of his potential diagnostic properties it is expedient to use a method of mathematical modeling, i.e. a method of studying of the phenomenon with the help of mathematical models. The minimal frequency of a trace of reflection from the Earth for higher than the main maximum ionograms is a critical frequency of an ionosphere. Ionograms from heights below a maximum of an ionosphere in most cases have the second trace of reflection from the Earth with the bigger group delay, which incorporates to the top trace of reflection from the Earth on the frequency determining plasma frequency near to the satellite. Vertical profiles of electron concentration both on gravitational vertical and aside of it, where ionosphere irregularity situated, were obtained. The goal of the present work is studying the new phenomenon on the basis of construction of mathematical models of the new phenomenon, which completely would explain all known features for the present moment. Sited mathematical model of an ionosphere irregularity defines lines of constant electron concentration and a direction of a gradient of concentration. The size of concentration between consecutive lines is identical one. Dependence of concentration on height along a vertical line under the satellite, and also on a number of verticals on the certain distances from the satellite is restored, namely the internal structure of irregularity is restored. Step-by-step method of ray tracing is used taking into account refraction and possible reflection of a wave on each line of constant concentration. It is caused by that is necessary to define a trajectory as the closed loop with beforehand known virtual distance. Conclusion. The described mathematical model enables to define physical conditions causing the related lower trace on ionograms. In its frameworks there are trajectories of the signals radiated from satellite, returning a signal back on the satellite. Virtual depth at vertical ionosonde signal propagation to the Earth corresponds to the group delay fixed on ionogram after reflection from the Earth. Virtual distances of returnable trajectories corresponds related lower traces on each of the investigated frequencies. The mathematical model explains also presence of set of traces on ionograms, which in usual conditions should be counted noise. They can be explained by presence of returnable signals on trajectories, which trace of group delays located far from a line of RLT. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.ursi.org/proceedings/procGA05/pdf/GP1.17(0268).pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
