Yu. F. Gagarin

The high-energy heavy-particle fluences in the orbits of manned space stations

The results are presented of measurements high-energy particles in a customary manned space station orbit (a 350-450-km altitude, a 51.6 degrees inclination; Salyut-6 and 7, MIR). The particles were recorded by the chambers composed of the Lavsan (polyethyleneterephtalate) solid-state nuclear track detector layers mounted outside a spacecraft for 1-3 years. A high resolution has been attained in the charge and energy spectra of 30-200 MeV/n Fe group particles. The results of measuring the particle fluxes in the space station orbits are used to restore the initial particle energy spectra in terms of the models that describe the galactic and solar cosmic rays and their penetration to the Earths magnetosphere. The analysis demonstrates a high effectiveness of the described methods when applied to quite a number of space physics problems.

Heavy particle fluxes in Salyut space station orbit.

Results of a detailed analysis of heavy ion fluences measured on the Salyut and MIR orbital stations from 1978 to 1990 are presented. The analysis has made use of new models that describe the cosmic ray fluxes and their transition through the magnetosphere. The penetration of solar cosmic ray particles to the orbit, the increase of the (Sc-Cr)/Fe flux ratio in the orbit, and the occurrences of 200-500 MeV/nucl heavy nuclei in <30 degrees latitudes have been analyzed.

Fluxes of GCR and SCR iron nuclei in the international space station orbit

The anticipated flux of iron nuclei and ions in the energy interval 26–168 MeV/nucleon in the orbit of the international space station (ISS) during the exposure of the PLATAN-M dielectric track detector from January 26, 2002, to August 3, 2004, has been estimated. The calculation is based on the data obtained using the SIS spectrometer onboard the ACE space station and the last version of the model describing the penetration of charged particles into the Earth’s magnetosphere. The time variations in the GCR iron nuclei intensity in the ISS orbit during solar cycle 23 have been obtained using the data of the PLATAN-4 and PLATAN-5 earlier experiments onboard the Mir space station.

Low energy heavy nuclei in Lavsan chamber on the salyut-7 space station in 1984–1985

Abstract Energy spectra of subiron (ScCr) and iron nuclei in the range 40–210 MeV/n have been measured and subiron to iron abundance ratio was determined from a study of a polyethyleneterephthalate (Lavsan) detector exposed in 1984–1985 during a year on the Salyut-7 space station. The ratio measured is ∼0.9 in the energy range 170–210 MeV/n that confirms previous data. The value differs from that 0.4-0.5 measured in interplanetary space. The ratio is ∼0.45 in the range 40–110 MeV/n. The peculiarities observed are discussed.

Energy spectra of low-energy solar iron particles measured in the orbit of the international space station in the period 2002–2004

The energy spectrum of iron is measured over the range of 30–150 MeV/nucleon using the PLATAN-M chamber consisting of solid-state track detectors mounted on the external surface of the International Space Station (ISS) in the period 2002–2004. The spectra of solar and galactic cosmic rays (SCRs and GCRs) are compared to the data from the SIS instrument on board the ACE spacecraft, transformed to the ISS orbit. Compared to the SIS data, the energy resolution of the PLATAN-M spectrum is twice better and the spread of experimental points is 50% lower.

Results of measuring the fluxes of solar energetic particles and methods of their interpretation

Reliability and credibility of the results of measurements of the fluxes of protons and heavy ions of solar energetic particles, carried out with various experimental methods, are studied, as well as the methods of description of obtained data with various model functions of energy spectra. We analyze the results of measuring the fluxes of heavy ions of solar cosmic rays with the use of solid-state track detectors in the experiments Astro (April 1981, Salyut-6 spacecraft) and Platan-3 (1988–1989, Mir orbital station) and compare them with the results of experiments VLET and CRT made onboard the IMP-8 satellite. Special emphasis is made on the analysis of results obtained with instruments SIS and ULEIS (ACE), and of results of measuring the fluxes of helium ions by the instrument EPEAD on GOES satellites. We also discuss the problem of fitting experimental data about SCR fluxes by different functions of energy (momentum, velocity) of particles. Such an approximation is a basis for interpreting the results of measurements. Numerous systematic errors are revealed that are typical for the results of measurements of the fluxes of SCR particles, performed with different instruments onboard Earth-orbiting satellites and other space vehicles.

Heavy-Nucleus Interactions at 4-1000 GeV/Nucleon and a Collective Mechanism of Multiple Particle Production

Interaction of cosmic ray nuclei of different charge (z = 4-8; z = 10-14; z = 20-28) with the Ag, Br and C, N, O nuclei was analysed. The energy dependence was obtained for the following multihadron production characteristics; (a) half-angles θ1/2π of meson emission; (b) meson multiplicity per interacting nucleon; (c) shower particle quasi-rapidity distributions; (d) width of the quasi-rapidity distributions of mesons. The heavy-nucleus interactions were compared with nucleon-nucleon and nucleon-nucleus interactions, at intermediate and minimum impact parameters. A theoretical approach based on the assumption of a collective nuclear interaction mechanism and on the recently developed model of multihadron production in elementary interactions was used to interpret the experimental results.

Evidence for existence of multiply charged argon ions in anomalous cosmic rays

The spectrum of Ar ions in anomalous cosmic rays in the energy range 14–42 MeV/nucleon was measured in the PLATAN-5 experiment at the Mir space station in 1994–1997. The spectrum is analyzed along with the data obtained by the SIS instrument on the ACE spacecraft in the circumterrestrial space. On the basis of the comparison of the spectra recorded within and beyond the magnetosphere, the average effective charge of ACR argon ions has been estimated. The estimate obtained is much larger than unity at energies exceeding 22 MeV/nucleon. The ion charge gradually increases with an increase in energy and reaches the value Q = 4 at an energy of 38 MeV/nucleon.

Investigation of heavy cosmic-ray nuclei by solid-state track detectors on orbiting platforms

Results are presented from investigations of Fe-group nuclei in galactic and solar cosmic rays in the energy ranges 30–210 MeV/n and 7–210 MeV/n in various phases of the solar cycles. Spectra of Fe particles have been obtained with high energy resolution as a result of exposing PLATAN chambers, made up of layers of a polyethyelene terephthalate solid-state track detector, for between one and three years on the Salyut-6, Salyut-7, and Mir space stations, orbiting at an inclination of 51.6° to the plane of the equator and at an altitude of 350–400 km. Measurements were made of the energy spectra of Fe particles from a unique event, the series of solar flares of September 29 and October 19–29, 1989, which is the most powerful of those recorded and measured over the entire history of cosmic ray research. A modern model of particle penetration inside the Earth’s magnetosphere, developed at the Institute of Nuclear Physics at Moscow State University, is used to compare the measured spectrum with measurements made using the solid-state track detector in the HIIS experiment on the LDEF station, and with extramagnetospheric measurements made using electronic equipment on the IMP-8 satellite and the Galileo space station. It is shown that the solid-state track detector technique has advantages for obtaining the characteristics of the energy spectrum.

ON THE NATURE OF NUCLEAR SCALING OF CUMULATIVE HADRON SPECTRA IN HADRON-NUCLEAR INTERACTIONS

An interpretation is given for the nuclear scaling of cumulative hadron spectra that provides an understanding of its nature and universality. A simple explanation is presented for the well-known remarkable fact: the spectra of cumulative protons also obey the nuclear scaling though their sources strongly differ from sources of mesons and antiprotons in physical parameters. This explanation has been found by analysing the channel of cumulative production of hadrons in the framework of the gluon-dominance model elaborated for describing the multihadron production.