Measurements of Energy of Cosmic-Ray Nuclei by Specific Energy Release at the Hadron Cascade Maximum

A method of measuring the particle energy in the range higher than 1 TeV based on detection of the maximum specific energy release in hadron cascades that develop in dense media is proposed and studied. This method makes it possible to improve the accuracy of energy measurements carried out with partial-absorption ionization calorimeters in the high-altitude studies of energy spectra of high-energy cosmic rays. The attainable accuracies of energy measurements are considered for light, intermediate, and heavy nuclei in iron and lead absorbers. The results of modeling are compared with the data of an experiment onboard the Kosmos-1713 satellite.     

Physical and Mathematical Simulation of Electric Polarization of Low-Orbit Spacecraft under the Conditions of Hypersonic Flow by a Stream of Plasma of the Earth's Upper Ionosphere

The charging processes in the vicinity of a low-orbital spacecraft moving in the midlatitude ionosphere are considered. It is shown that the main feature of charging of such an object is its polarization. The calculation results are analyzed in the context of general theoretical concepts.     

Mechanics of Zero Gravity and Gravitationally Sensitive Systems (First Issue)

This issue of the journal contains papers with the results of studying gravitationally sensitive systems and processes under conditions of microgravity aboard the Mirorbital complex. This is one of the most difficult field of space research whose difficulties are due to both complexity of the object of investigations (since the class of gravitationally sensitive systems and processes is fairly wide, and some of them are not sufficiently studied even under terrestrial conditions) and necessity of using expensive instrumentation and carrying out long-term experiments. However, studying the new mechanical state of weightlessness is inevitable in space exploration. In addition, in some cases it can provide for a new knowledge about the fundamental laws of nature. By virtue of the above reasons, the experiments on microgravity are well presented in the research program onboard the International Space Station.There is a long tradition in this field of research in Russia, and the experience of Russian scientists (a part of which is presented in the papers of this issue) allows them to pass on to the next, better technically equipped, stage of investigations in cooperation with the scientists from other countries.This issue is prepared by an initiative of the subsection Mechanics of zero gravity and gravitationally sensitive systemsof the Coordination Scientific and Technical Council (CSTC) of the Russian Agency for Aviation and Space Flights (Rosaviakosmos).     

Population inversion and gain distribution in supersonic mixed flow systems

Experimental results are reported for small signal gain distribution across a cavity of a mixed flow gasdynamic laser system at different turbulent supersonic mixing regimes. It is shown that the temperature range of the GDL generation regime can be extended up to 7000°K, and gain coefficients as high as 3.5 m⁻¹ be attained in a “double-freeze” supersonic gas flow. Basic advantages are discussed as well as the opportunity to obtain higher efficiencies in thermally pumped laser systems.     

Recent progress in studies of DMSP auroral photographs

A new auroral pattern, which indicates major auroral characteristics in all local time sectors, is presented. It has emerged as a result of extensive study of DMSP-8531 and -10533 auroral photographs. The paper presents also a brief summary of recent studies on the role of the north-south component of the interplanetary magnetic field on large-scale auroral dynamics and on the relationship between substorm energy and the size of the oval.     

Simulation of space cabin atmosphere

The Soyuz 22 space cabin atmosphere was studied for volatile organic trace contaminants. By gas chromatography the following constituents were identified: methane, ethane, heptane, methanol, ethanol, n-propanol, acetaldehyde, acetone, ethyl benzene. Except for acetone, concentrations of the above compounds were close to the values determined in the mock-up experiments.     

Comparison of computational and experimental results in vibroacoustic active control using piezoelectric film technology

The present investigation concerns control of far-field acoustic radiation generated by a thin plate in a broad frequency band using piezoelectric films. System dynamics is of modal nature.This paper describes a comparison of numerical and experimental results for a closed loop type control. This comes from Optimal Control Theory via radiation filter causal transformation based on a dissipative criterion.     

Vertical distribution of SO2 in upper cloud layer of Venus and Origin of U.V.-absorption

It is shown that decline of spherical albedo of Venus toward the ultraviolet can be explained by the presence of two absorbing agents: a) SO₂, for which abundance is 10¹¹ cm^?3 at height 68 km and scale height is about 1 km; b) some unknown aerosol absorbent, possibly a 1% FeCl₃ admixture in a sulfuric acid concentrated solution. A mechanism of aerosol formation is proposed.     

Extreme ultraviolet observations of the solar corona: First results from the coronal diagnostic spectrometer on SOHO

We present first results from the Coronal Diagnostic Spectrometer (CDS) aboard the ESA/NASA Solar and Heliospheric Observatory (SOHO). CDS is a double spectrometer operating in the 151–785 Å range. This region of the solar spectrum is rich in emission lines from trace elements in the solar atmosphere, which can be used to derive diagnostic information on coronal and transition region plasmas. Early spectra are presented and well identified lines are listed. In addition, examples of images in selected wavelength ranges are shown, for a prominence, a loop system and a bright point, demonstrating well the power of such extreme ultraviolet observations.