The main goal of the Vernov mission is the study of magnetospheric relativistic electron precipitation and its possible influence on the upper atmosphere as well as the observation of Transient Luminous Events (TLE) and Terrestrial Gamma Flashes (TGF) across a broad range of the electromagnetic spectrum.The RELEC (Relativistic Electrons) instrument complex onboard the Vernov spacecraft includes two identical X- and gamma-ray detectors of high temporal resolution and sensitivity (DRGE-1 and DRGE-2), three axis position detectors for high-energy electrons and protons (DRGE-3), a UV TLE imager (MTEL), a UV detector (DUV), a low frequency analyser (LFA), a radio frequency analyser (RFA), and AN electronics module responsible for control and data collection (BE).The RELEC mission conducts the following experiments:- simultaneous observations of high-energy electron and proton fluxes (within the energy range of similar to 0.1-10.0 MeV) and low-frequency (similar to 0.1-10 kHz) electromagnetic wave field intensity variations with high temporal resolution (similar to 1 ms);- fine time structure (similar to 1 mu s) measurements of transient atmospheric events in UV, X- and gamma rays with an optical imaging capability with a resolution of similar to 1 km in wide field of view (FOV);- measurements of electron flux pitch-angle distributions in dynamical ranges from similar to 0.1 up to 10(5) part/cm(2)/s;- monitoring of charged and neutral background particles in different areas of near-Earth space. (C) 2015 COSPAR. Published by Elsevier Ltd. All rights reserved.

Properties of the waves, which can propagate in a magnetized plasma in the frequency range below the proton gyrofrequency, depend strongly on the ion composition of the plasma. Addition of a new sort of ions leads to the appearance of a new resonance frequency, at which the refractive index becomes infinite, and a new cutoff frequency, at which the refractive index becomes zero. In this case, the topology of frequency dependence of the squared refractive index changes. Specifically, a new oscillation branch appears, which is located above the cutoff frequency. A question arises whether these oscillations are excited if radiation with the corresponding frequency, which propagates in a different mode, is present in the plasma. A linear transformation of the waves is another important effect, which is related to variations in the ion plasma composition. These two issues, which are directly related to the theory of formation of proton whistlers in the ionosphere, where the ion composition varies with altitude, are considered in this work.

We present the first experimental results on the observation of optical transients, gamma-ray bursts, relativistic electrons, and electromagnetic waves obtained during the experiment with the RELEC complex of scientific equipment on the Vernov satellite.

We present observations of “normal” and “abnormal” (solitary) Trans-Ionospheric Pulse Pairs (TIPPs) recorded by microsatellite “Chibis-M”. Measurements made by Radio Frequency Analyzer (RFA) onboard “Chibis-M” with passband 26–48MHz and digitization 96MHz. It is widely supposed that TIPPs appear as pairs of short (up to 10–20μs) VHF bursts separated by a few tens of microseconds. Dispersion of the signal indicates on its sub-ionospheric origin. It was proved by previous space-borne missions (ALEXIS and FORTÉ) that doubling of the signal results from the reflection of initial VHF emission from the surface. Nature of the TIPPs source is still under discussion. In this paper we are arguing that “solitary” VHF impulses from the sub-ionospheric source identified also in ALEXIS data represents the coalescence of two separate VHF bursts of TIPP. Observations of this phenomena are possible only for some specific geometrical patterns (low elevation of the source and high observational angle relative to the satellite position). We present some quantitative analysis to verify this hypothesis and found reasonably good correspondence of theory and observations.

В статье отражены научные задачи и конструкторские разработки микроспутниковой платформы Чибис и комплекса научной аппаратуры “Гроза”, направленные на изучение новых физических механизмов высотных электрических разрядов в атмосфере. Приводится описание комплекса научной аппаратуры “Гроза”, который является единым “летающим” прибором, определяющим основные требования к микроспутнику Чибис-М. Изложены вопросы наземной подготовки космического эксперимента, методики вывода в инфраструктуре МКС микроспутника на орбиту, командно-телеметрического управления в полете, приведены первые научные результаты.

This paper describes the scientific goals and design developments of the Chibis microsatellite platform and the Groza scientific equipment, which are aimed at studying new physical mechanisms of high-altitude electrical discharges in the atmosphere. A description of the Groza scientific equipment is presented, which is a united flying instrument that determines the basic requirements for the Chibis-M microsatellite. The problems of ground training of the space experiment, methods of launching the microsatellite in the ISS infrastructure into orbit, and command and telemetry control in flight, as well as the first scientific results, are presented.

We present experimental observations and detailed investigation of the variety of proton whistlers that includes transequatorial and ionospherically reflected proton whistlers. The latter have previously been indicated from numerical modeling of spectrograms. The study is based on six‐component ELF wave data from the Detection of Electro‐Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite which permits to obtain not only spectrograms displaying the power spectral density but also such wave properties as the polarization, wave normal angle, wave refractive index, and normalized parallel component of the Poynting vector. The explanation of various types of proton whistlers is based on the properties of ion cyclotron wave propagation in a multicomponent magnetoplasma, with special consideration of the effect of ion hybrid resonance reflection. Analysis of experimental data is supplemented by numerical modeling of spectrograms that reproduces the main features of experimental ones. As a self‐contained result, we provide conclusive experimental evidences that the region illuminated by a lightning stroke in the Earth‐ionosphere waveguide may spread over a distance of 4000 km in both hemispheres.

Based on observations from the DEMETER satellite, we present and investigate various types of proton whistlers, including ionospherically reflected proton whistlers, which have not been discussed so far. The observations are complemented by theoretical analysis and numerical simulations. A side result of the analysis consists in that the region in the Earth-ionosphere waveguide illuminated by a lightning stroke, which serves as an effective source of the emission, spreads more than 30 degrees over latitude in meridian plane.

Variations of plasma distribution and/or wave spectral features in the ionosphere were suggested by many authors as possible earthquake precursors, and the change of plasma density and temperature above seismic regions were reported in the literature. These quantities are known to influence the lower hybrid resonance (LHR) frequency profiles in the upper ionosphere and the magnetosphere, which, in turn, strongly affects the propagation of quasi-resonance VLF waves with frequencies f close to the maximum of the LHR frequency on the propagation path. This makes the VLF signals a tool of registration of ionospheric perturbations. Using the measurements from the DEMETER satellite for 3yr we have calculated the maps of LHR frequency over the globe, and the maps of VLF spectral intensity at the frequencies of Alpha navigation transmitters. These maps demonstrate a significant dependence of the spectral intensity in the transmitter conjugate region on the relation between the signal frequency and the LHR frequency above the observation point. Then, using the DEMETER data and the earthquake database from the US geological survey server we have performed statistical analysis of the LHR frequency over seismic regions and found an appreciably different behaviour of the LHR frequency before earthquakes, as compared to its regular behaviour, for several seismic regions. Although this difference is statistically significant, in each particular case the ionospheric perturbations may be related to different processes in the Earth's atmosphere, ionosphere, and the magnetosphere, other than gathering earthquakes. Thus, the unexpected variations in the LHR frequency profile, revealed from the variations of VLF transmitter signals, should only be considered as one indicator in a list of possible earthquake precursors.