O. R. Grigoryan

Investigations of the space environment aboard the Universitetsky-Tat’yana and Universitetsky-Tat’yana-2 microsatellites

The first results obtained through the university small satellites program developed at Moscow State University (MSU) are presented. The space environment was investigated aboard two MSU microsatellites designed for scientific and educational purposes, Universitetsky-Tat’yana and Universitetsky-Tat’yana-2. The scientific equipment is described to study charged particles in near Earth space and atmospheric radiations in ultraviolet, red, and infrared optical wavelength ranges. The dynamic properties of fluxes of charged particles in microsatellite orbits are studied and findings are presented regarding specific parameters of solar proton penetration during the geomagnetic disturbances. Experimental results are considered concerning flashes of ultraviolet (UV), red (R), and infrared (IR) radiation that are transient light phenomena in the upper atmosphere. The space educational MSU program developed on the basis of the Universitetsky-Tat’yana projects is reviewed.

Low-energy charged particles at near equatorial latitudes according to “MIR” orbital station data

Some date analysis results obtained by means of the “SPRUT-V” device, mounted onboard the orbital station “MIR” in Jan. 1991 are presented. This device measures the energy distribution of Ee>35,>75,>300,>600 keV electron fluxes and Ep=0.1…8.0 MeV proton fluxes. Special attention is given to: 1. The registration of electron fluxes with energy of tens and hundreds of keV at L 75 keV sporatic electron fluxes at L<1.5, conjugate to the Brazil anomaly area. 3. The registration of proton fluxes at about all longitudes near the geomagnetic equator at L<1.3.

Low energy protons on L≤1.15 in 500 – 1500 km range

The results of low-energy ( 1.04. The characters of proton distributions with energies Ep>100 keV and Ep<100 keV are strongly different. There are features of altitude distribution connected with geomagnetic activity level: during quiet time at night hours all energy protons registered at all altitudes, at day hours the most intensive proton fluxes of were registered at 700–900 km; during disturbed time at night hours they are absent at 900–1100 km, whereas at day hours the essential high-energy proton fluxes appears only at 700 km

Energetic electrons on L<1.2 connection to lightning activity?

Abstract Electron fluxes measurements with energies of tens-hundreds keV in the region of geomagnetic equator are presented. The possibility of the influence of lightning discharges on the inner radiation belt electrons fluxes distributions is analysed. The particle data are compared with existing experimental data of E dc measurements (in some experiments, fields up to 100 mV/m have been measured) and low frequency electromagnetic fields (up to 0.5 MHz) in the equatorial region.

INVESTIGATION OF MAGNETOSPHERIC PROCESSES WITH THE USE OF A SOURCE OF STRONG MAGNETIC FIELD IN THE IONOSPHERE

Abstract More than 20 years ago V.P. Shabansky suggested that the magnetic system installed aboard the satellite, could be used as a physical instrument for studying the processes which occur in the near Earth space. The corresponding space scales of an artificial “magnetosphere”—“magnisphere”—are ∼ 10 m in the experiment with relatively small magnets in the ionosphere and ∼ 100 m in the solar wind. The corresponding similarity criteria are estimated. The possible scheme of the experiment with a superconducting magnet (magnetic moment ∼ 10 5 A · m 2 ) installed aboard the satellite is considered. The experimental complex includes a number of systems for measuring the fluxes of charged particles in a wide energy range, DC electric and magnetic fields, the electromagnetic fields in different frequency bands (from X-rays to radio). The scientific objectives are discussed in detail.

UV Radiation from the Night-Time Atmosphere seen from the “Universitetsky-Tatiana” Satellite

Detectors on the “Universitetsky‐Tatiana” satellite measured a smoothly varying intensity of UV radiation from the night‐time atmosphere in the nadir direction and the intensity of the energetic electron flux at the orbit. At high latitudes the UV intensity in the auroral oval is interpreted as being due to electrons penetrating into the atmosphere. At middle latitudes the UV intensity is an order of magnitude less and more data are needed to reveal the origin of this radiation. Millisecond flashes of UV radiation were observed. The flashes’ energy, temporal profile and global distribution are similar to these parameters for Transient Luminous Events (TLEs). These studies will be continued aboard the next satellite “Tatiana‐2”.

Near-Equatorial Electrons as Measured onboard the MirSpace Station

Some results of studying the electrons with energies of tens to hundreds of keV at the low and near- equatorial geomagnetic latitudes by using the instruments Sprut-V and Ryabina-2 onboard the Mirspace station in 1991 are presented. It is found that at L< 1.2 the enhanced electron fluxes are sporadically detected, being localized within three longitudinal intervals, 180° W–0°–15° E, 90°– 120° E, and 160° E–180°–135° W. The most intense electron fluxes are observed at the lower edge of the near-equatorial boundary of the inner radiation belt on longitudes of the South Atlantic Anomaly between 14 and 20 h MLT. The occurrence of electron bursts does not depend on the geomagnetic disturbance level. A hardening of the electron spectra is observed near the geomagnetic equator. At L< 1.1, the more energetic particles are located closer to the geomagnetic equator. The results are compared with the data on the low-frequency waves and fields at low and near-equatorial latitudes obtained by the Ariel-4and San Marco Dsatellites, as well as by the spacecraft and ground-based observations of the thunderstorm global distribution. The thunderstorms are considered as a possible source of electron production near the geomagnetic equator.

Energetic Particles Impacting the Upper Atmosphere in Connection with Transient Luminous Event Phenomena: Russian Space Experiment Programs

In Russia several space missions are now planned to study transient luminous events in the atmosphere and high energy charged particles at satellite altitudes. The experimental goal is to investigate the origin of the high energy electrons and gamma‐ray quanta for specific transient luminous events (TLEs) and their role in the ionosphere‐magnetosphere system. Simultaneous measurements of electrons at the orbit of the satellite and TLE atmospheric radiation in many wavelength bands will be performed in two missions, Tatiana‐2 and RELEC. In the TUS mission UV transient event detection will be accompanied by measurements of the weak UV emission from the “seed” electrons of extensive air showers of extremely high primary energies.

Electron Flux Formations at Middle Latitudes in the Surface Dose of Spacecraft

In this work experimental data on electron fluxes with energies of 30-500 keV obtained from the ACTIVE satellite experiment (INTERCOSMOS-24 in 1989-1990, altitude from 500 km up to 2500 km) and ones with energies 0.3-1.0 MeV obtained onboard the MIR station (SPRUT-VI experiment in 1999, altitude from 350 km up to 400 km) are presented. The distribution of electron fluxes at low and middle latitudes and the influence of charged particles on surface layers of materials and film coverings are investigated. The comparison with results of other satellite experiments reveals the time and spatial stability of electron flux enhancements at L = 1.2-1.8.

The Wave Complex of the СПРУТ-VI Instrument Package

The wave complex of the СПРУТ-VI instrument package was designed for monitoring the electromagnetic state around orbital stations. The method of combined wave probes enables simultaneous vector measurements of magnetic field fluctuations (in a frequency range from 0.1 Hz to 40 kHz) and the electric current density in plasma (in a range of 10–6–10–13 А cm–2), as well as determination of the station surface potential (in a range of 10–3–20 V). The complex was used onboard the Mir station for investigating the fine structure of distributions of ionospheric charged particles at low and near-equatorial latitudes.