Anomalous Decimeter Radio Noise from the Region of the Atmospheric Front: I. Characteristics of the Detected Radio Noise and Meteorological Parameters of the Frontal Cloudiness

An extraordinary experimental fact is presented and analyzed, namely, a rather intense broadband radio noise detected during the passage of an atmospheric front through the field of view of UHF antennas. Local atmospheric properties and possible sources of the extraordinary noise, including the thermal noise from cloudiness and extra-atmospheric sources, are considered. A conclusion is made about the presence of an additional nonthermal source of radio noise in the frontal cloudiness. According to the proposed hypothesis, these are multiple electric microdicharges on hydrometeors in the convective cloud.     

Global modelling study (GSM TIP) of the ionospheric effects of excited N2, convection and heat fluxes by comparison with EISCAT and satellite data for 31 July 1990

Near-earth plasma parameters were calculated using a global numerical self-consistent and time-dependent model of the thermosphere, ionosphere and protonosphere (GSM TIP). The model results are compared with experimental data of different origin, mainly EISCAT measurements and simultaneous satellite data (N_e and ion composition). Model runs with varying inputs of auroral FAC distributions, temperature of vibrationally excited nitrogen and photoelectron energy escape fluxes are used to make adjustments to the observations. The satellite data are obtained onboard Active and its subsatellite Magion –2 when they passed nearby the EISCAT station around 0325 and 1540 UT on 31 July 1990 at a height of about 2000 and 2200 km, respectively. A strong geomagnetic disturbance was observed two days before the period under study. Numerical calculations were performed with consideration of vibrationally excited nitrogen molecules for high solar-activity conditions. The results show good agreement between the incoherent-scatter radar measurements (N_e, T_e, T_i) and model calculations, taking into account the excited molecular nitrogen reaction rates. The comparison of model results of the thermospheric neutral wind shows finally a good agreement with the HWM93 empirical wind model.     

The Space System for Remote Sensing of the Earth Based on the <Emphasis Type="Italic">Arkon</Emphasis> Satellite (On the 20th Anniversary of the First Launch)

On the eve of the 20th anniversary of the first launch of the Arkon satellite, the article provides a retrospective of the birth, implementation, and development of this unique project that has no comparable counterparts. The authors also single out those remarkable teams of developers and their leaders whose activities have become part of the history of the Lavochkin Research and Production Association and its pride.     

The Correlation of Temperature,Stratus Cloudiness,and Electric Field Strength in the Atmosphere

Doklady Earth Sciences - This paper presents the results of observations and processing of experimental data on long-term (2012–2018) continuous electric field measurements and compares them...     

Numerical simulation of the electric field and zonal current in the Earth’s ionosphere: The dynamo field and equatorial electrojet

The work is devoted to the numerical simulation of the dynamo electric field and its effects in the Earth’s ionosphere within the scope of the thermosphere-ionosphere-protonosphere global self-consistent model developed at WD IZMIRAN. The new electric field calculation block, which was used to obtain results of the self-consistent calculations of the electric field potential generated by the dynamo effect of the thermospheric winds (the dynamo field) and the equatorial electrojet for March 22, 1987, is briefly described in this work. A comparison of the obtained results with the experimental data showed a satisfactory agreement. Moreover, the proposed model was used to calculate the diurnal variations in the ionospheric parameters for Jicamarca equatorial station under the same conditions with the help of the new block of the electric field. The results of these calculations are also presented and discussed in this work. It has been indicated that the new model satisfactorily describes the specific features of electric field distribution at the geomagnetic equator and the well-known phenomenon of equatorial electrojet.     

Phase effect for the brightness coefficient of the central disk of Saturn and features of Jupiter's disk

Spectral reflectivities ?(λ) of the features on the disk of Jupiter (NTrZ, NEB, EZ, SEB, STrZ) and the center of the disk of Saturn were measured for different phase angles. The phase dependence of ?(λ) is shown to correspond to the shape of the phase function.     

Estimation of physical conditions in the cold phase of the interstellar medium in the sub-DLA system at <Emphasis Type="Italic">z</Emphasis> = 2.06 in the spectrum of the quasar J 2123–0050

An independent analysis of the molecular hydrogen absorption system at redshift z _abs = 2.059 in the spectrum of the quasar J 2123?0050 is presented. The H₂ system consists of two components (A and B) with column densities \(\log N_{{H_2}}^A = 17.94 \pm 0.01\) and \(N_{{H_2}}^B = 15.16 \pm 0.02\). The spectrum exhibits the lines of HDmolecules (logN _HD ^A = 13.87±0.06) and the neutral speciesCI and Cl I associated with the H₂ absorption system. For the molecular hydrogen lines near the quasar’s Lyβ and OVI emission lines, we detect a nonzero residual flux, ~3% of the total flux, caused by the effect of partial coverage of the quasar’s broad-line region by an H₂ cloud. Due to the smallness of the residual flux, the effect does not affect the H₂ column density being determined but increases the statistics of observations of the partial coverage effect to four cases. The uniqueness of the system being investigated is manifested in a high abundance of the neutral species H₂ and CI at the lowest HI column density, logN _HI = 19.18 ± 0.15, among the highredshift systems. The H₂ and CI column densities in the system being investigated turn out to be higher than those in similar systems in our Galaxy and theMagellanic Clouds by two or three orders ofmagnitude. The \(N_{HD} /2N_{H_2 }\) ratio for component A has turned out to be also unusually high, (4.26 ± 0.60) × 10^?5, which exceeds the deuterium abundance (D/H) for high-redshift systems by a factor of 1.5. Using the HI, H₂, HD, and CI column densities as well as the populations of excited H₂ and CI levels, we have investigated the physical conditions in components A and B. Component A represents the optically thick case; the gas has a low number density (~30 cm^?3) and a temperature T ~ 140 K. In component B, the mediumis optically thin with n _H ≤ 100 cm^?3 and T ≥ 100 K. The ultraviolet (UV) background intensity in the clouds exceeds the mean intensity in our Galaxy by almost an order ofmagnitude. A high gas ionization fraction, \(n_{H^ + } /n_H \sim 10^{ - 2}\), which can be the result of partial shielding of the systemfrom hard UV radiation, is needed to describe the high HD and CI column densities. Using our simulations with the PDRMeudon code, we can reconstruct the observed column densities of the species within the model with a constant density (n _H ~ 40 cm^?3). A high H₂ formation rate (higher than the mean Galactic value by a factor of 10?40) and high gas ionization fraction and UV background intensity are needed in this case.     

Preliminary design of pseudo satellites: Basic methods and feasibility criteria

Analytical models of weight and energy balances, aerodynamic models, and solar irradiance models to perform pseudo-satellite preliminary design are presented. Feasibility criteria are determined in accordance with the aim of preliminary design dependent on mission scenario and type of payload.