V. I. Tulupov

First results of investigating the space environment onboard the Universitetskii-Tatyana satellite

The complex of scientific pay load installed onboard the research and educational Universitetskii-Tatyana microsatellite of Moscow State University is described. The complex is designed to study charged particles in the near-earth space and ultraviolet emissions of the atmosphere. Data of the measurements of charged particle fluxes in the microsatellite orbit are presented, spectra are calculated, and the dynamics of penetration boundaries for protons of solar cosmic rays (SCR) during geomagnetic disturbances in 2005 is investigated. Intensities of the ultraviolet emission are measured in the entire range of variation of the atmospheric irradiation, as well as intensities of auroras in the polar regions of the Northern and Southern hemispheres. The experimental data on flashes of ultraviolet radiation (transient light phenomena in the upper atmosphere) are considered, and some examples of oscillograms of their temporal development and their distribution over geographical coordinates are presented.

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.

Atmospheric ultraviolet and red-infrared flashes from Universitetsky-Tatiana-2 satellite data

Millisecond ultraviolet (240–400 nm) and red-infrared (610–800 nm) flashes were detected in the nighttime atmosphere with the scientific payload installed onboard the Universitetsky-Tatiana-2 micro-satellite. Flashes with various numbers of photons, from 1020 to 1026, were detected within the atmospheric area 300 km in diameter observed by the detector. The flashes differ in duration and temporal profile: from single short flashes ∼1 ms in duration to flashes with a complex profile more than 100 ms in duration. Different global geographic distributions are observed for flashes with different numbers of photons. Flashes with fewer than 1022 photons are distributed uniformly over the Earth’s map. Flashes with more than 1022 photons are concentrated near the equator and above the continents. Series of flashes were observed in one turn of the satellite when flying not only over thunderstorm regions but also over cloudless ones. The flash number distribution has been derived from the ratio of the numbers of red-infrared and ultraviolet photons. As applied to discharges in the upper atmosphere, whose glow is dominated by the emission in the first and second positive systems of molecular nitrogen bands (1PN2 and 2PN2), this distribution is equivalent to the flash altitude distribution in the atmosphere. The observed ratio of the numbers of photons in red-infrared and ultraviolet flashes agrees with the calculated one for electric discharges at altitudes higher than 50 km. In-orbit measurements of the charged particle flux (with a threshold energy for electrons of 1 MeV) provide no evidence for a synchronous occurrence of an ultraviolet flash and a burst in the particle flux in the orbit.

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”.

Penetration of solar cosmic rays into the Earth’s magnetosphere on January 28, 2012

Results of the comparative analysis of the dynamics of SCR fluxes with energies of 1–100 MeV in the interplanetary environment according to the data of the ACE and Wind spacecraft and within the Earth’s magnetosphere according to the data of the GOES-15 and Electro-L satellites in the region of geostationary orbits, and POES-19 and Meteor-M1 in the region of polar caps during two increases in SCR of January 19–31, 2012, are presented. It is shown that the decrease in the efficiency of SCR penetration into the Earth’s magnetosphere in the region of the orbits under study on January 28, 2012, is related to the passage of the Earth’s magnetosphere through the interplanetary environment structure with a quasi-radial interplanetary magnetic field and a small pressure of the solar wind.

Some features of solar cosmic ray penetration into the Earth’s magnetosphere

We compared fluxes of the 1–100 MeV solar energetic particles (SEP) measured in the interplanetary medium (ACE) and in the magnetosphere (Universitetsky-Tatiana, POES—in polar caps, and GOES-11—at geosynchronous orbit) during several SEP events of 2005–2006. Peak intensities of the SEP fluxes inside and outside the magnetosphere were compared for each event. It is shown that observed inside-outside difference depends mainly on direction of interplanetary magnetic field (IMF), on degree of the SEP anisotropy (pitch-angle distribution) in IMF, and on distance of the dayside magnetopause from the Earth.

Specific features of solar cosmic ray fluxes and geomagnetic conditions on December 5–18, 2006

Results of the analysis of specific features of solar activity, dynamics of solar cosmic ray fluxes, and state of the interplanetary medium are presented for the period December 5–18, 2006. The data analysis is based on new model concepts on coronal and interplanetary propagation of solar cosmic rays: partial capture into the magnetic field traps and oscillations at reflections from magnetic mirrors. Some new hypotheses about possible relations of the features of the interplanetary medium with processes in the Earth’s magnetosphere are put forward: the influence of the discrete interplanetary medium on processes in the Earth’s magnetosphere does exist always and, in this sense, it is a fundamental phenomenon; the discreteness of the inter-planetary medium can be one of the causes of geomagnetic substorms.

Atmospheric Ultraviolet Light and Comparison of its Intensity with the Variation of Electron Flux with Energies Higher than 70 KeV in Satellite Orbit (According to Universitetskii-Tatiana Satellite Data)

The ultraviolet radiation of the night atmosphere and electron fluxes with energies higher than 70 keV are measured simultaneously onboard the satellite Universitetskii-Tatiana. It has been revealed that the mean intensity of ultra-violet radiation increases and this could be due to electron acceleration in atmospheric electric discharges with further capture by the geomagnetic field and electron precipitation in conjugated points of the geomagnetic field.

Transient flashes of electromagnetic radiation in the upper atmosphere

Experimental data related to electric discharges in the upper atmosphere are considered. These discharges occupy enormous volumes of the atmosphere (up to 1000 km3) and are accompanied by optical radiation (in the UV, optical, and IR ranges), and also by gamma-ray radiation. Possible physical processes responsible for the evolution of such discharges are also considered.

PREPARATION OF THE TUS SPACE EXPERIMENT FOR UHECR STUDY

We report on the current status of the TUS space mission project: its goals and the progress achieved so far. The Fresnel mirrors design, performed checks and their production are discussed. Also we discuss our future plans including auxiliary analysis of the fluorescence light yield measured this year by LAPP (Annecy), JINR (Dubna) and LIP (Lisbon) MACFLY Collaboration.