In the active ionosphere geophysical experiment "North Star" by injection of a high-speed plasma jet, luminescence of the excited components of the surrounding air was observed. In this paper, two possible sources of excitation of this luminescence are considered: streams of super-thermal electrons accelerated at the jet front and streams of precipitating electrons, the precipitation of which is triggered by jet injection. Detailed analysis of experimental data allows us to separate these two sources of super-thermal electrons. The origin of electrons forming at the front of an expanding plasma jet is associated with nonlinear processes in this area and will be discussed in detail in subsequent publications. This paper analyzes the mechanisms of electron precipitation from the upper ionosphere.
KEYWORDS: Atmospheric modeling, Solar radiation models, 3D modeling, Solar processes, Physics, Climatology, Satellites, Atmospheric chemistry, Radio propagation
We review the contemporary level of the lower ionosphere study. The progress in ionosphere physics is based on the complex measurements as well as on the self-consistent 3D computer codes but this is not the case for the lower ionosphere. We point out the problems which are necessary for the solar-terrestrial links, transient electrooptical events in the middle atmosphere and even for the global climate community models. Special attention is paid to the problem of verification using satellite and ground-based evidence. The examples from VLF-LF monitoring prove the requirement of further study of the lower ionosphere processes.
KEYWORDS: Solar radiation models, Solar processes, Ionization, Transmitters, Numerical simulations, X-rays, Data modeling, Monte Carlo methods, Physics
The progress in the physics and chemistry of the lower ionosphere depends on the verification of the numerical models on the experimental data. We establish the framework, that the lower ionosphere model can be considered as a valid one, only if the prediction for the VLF-LF radiowave propagation coincides with evidence both in amplitude and phase temporal dynamics. The extremely strong X-flares 06 and 10 September 2017 were chosen as a testbed for the empirical and theoretical models of the midlatitude lower ionosphere. Both models used GOES-15 X-ray flux measurements. Empirical model captures only the time moment of disturbance. Theoretical model captures the main feature in VLF response. We summarize the observed problems in simulation and prospective solutions as well.
The report analyzes the optical data received by the MSX satellite during Fluxus and North Star active rocket experiments, conducted in 1997 and 1999 on the injection of high-speed plasma jets into the ionosphere. It has been demonstrated that 1 to1.5 seconds after injection, the irradiation of the background medium increases. The brightness of the luminescence is associated with the bursts of the flow of precipitated electrons, stimulated by injection of a plasma jet.
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