The paper presents the results of measurements of the electric field and vertical atmospheric currents in conditions of "fair weather" and their comparison with the Carnegie curve. The features of the measurement data associated with the detection of the evening maximum of the electric field strength are shown.
The paper presents the variations in the parameters of the ionosphere D-layer during x-ray flares of M and X classes on the propagation path of signals from the superluminal waves of the GQD and GBZ transmitters, as well as those adopted by the Mikhnevo State Educational Center. It is shown that, within the framework of the two-parameter Ferguson-White model, the effective reflection height of the VLF signal h’ and the gradient of increase in the electron concentration β at the leading edge of the flare are related to the x-ray energy in the range 0.05–0.4 nm.
In September 2017, several X-class solar X-ray flashes occurred. The paper presents the variations of the parameters of the D-layer of the ionosphere during X-ray X-ray flashes on the propagation path of signals from the VLF GQD and GBZ transmitters, and received in the geophysical observatory "Mikhnevo". The dependences of variations in the parameters of the ionosphere from the X-ray flux in different ranges are obtained. It is shown, that the dependences of the parameters of the ionosphere (effective reflection height and electron density increase rate with height) versus the Xray flux in the ranges of 0.05–0.4 nm and 0.1–0.8 nm are very different for different solar X-ray flashes. This may be due both to different initial states of the ionosphere and to the fact that the X-rays radiation with wavelength less than 0.05 nm can play a major role in the ionization of the atmosphere at altitudes of 50-60 km.
Properties of the Schumann resonances have been extensively studied in order to explain their relation with properties of the upper atmosphere and ionosphere. This paper presents the results of an analysis of the frequency variations of the 1st mode of the Schumann resonator in two (North-South and East-West) magnetic field components in the geophysical observatory “Mikhnevo” during solar X-ray flares of M and X classes in 2011–2017. An analysis was made for the influence of the illumination of the signal propagation path and the total electronic content on it on the response magnitude of the variation of the first Schumann resonance frequency. It is shown that the frequency variation of the first mode of the Schumann resonance depends on the helio-geophysical conditions on the signal propagation path, i.e. arc of great circle. It is also shown that the diurnal variation of the sensitivity of the frequency variation of the 1st Schumann resonance to the X-ray flash power correlates well with the diurnal variation of the total electron content of the ionosphere on the signal propagation path. This fact may indicate that the electromagnetic wave at the frequencies of the first Schumann resonance penetrates into the upper ionosphere, namely into the f-layer. And, thus, the characteristics of the F-layer of the ionosphere can affect the parameters of the first Schumann resonance.
The use of global satellite navigation systems for the study of the ionosphere makes it possible to obtain information on ionospheric disturbances and to build maps of the distribution of large-scale ionospheric disturbances. The task of studying small and medium-scale inhomogeneities requires the creation of special methods of measurement and analysis. The system of receivers located at a distance of several hundred meters to 80 km from each other is used in the geophysical Observatory "Mikhnevo" (MIC, 54.9617° N, 37.7626° E) of the Institute of Geosphere dynamics of the Russian Academy of Sciences (http://idg.chph.ras.ru/ru/watch/mikhnevo). The obtained data allow us to estimate the velocity and trajectory of ionospheric inhomogeneity. The development of this approach in methodological terms will clarify the physical mechanisms of transmission of disturbances in the middle latitudes, which should allow to take them into account in the development and improvement of predictive models of ionospheric disturbances.
Solar flare on September 6, 2017 was one of the strongest in recent years. The powerful X-ray and ultraviolet radiation of the flash caused significant effects in the upper and lower ionosphere, in the geomagnetic field and surface electric field. The interrelation and spatio-temporal distribution of geophysical disturbances induced up by the flare and their influence on the accuracy of positioning of global navigation satellite systems are shown.
We study the surface electric field and the vertical atmosphere current at “Mikhnevo” geophysical observatory by means of a sensor cluster. The electric current sensor allows to disambiguate the displacement and conductive currents and to study their variations in sense of geophysical conditions. Data obtained under "fair weather" conditions and under significant perturbations are presented.
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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