Division of radiation and computational methods

Сокращенное название: DRCM

Телефон: +7 495 939 35 53


Division of Radiation and Computational Methods

The Department of Radiation and Computational Methods (DRCM) was organized in 1968 by Professor, Sc.D. Igor Ivanenko. Since 1993 till present it is headed by Sc.D. Alexey Kropotkin.

The scientists of the Division are specialized in two basic directions of SINP MSU activity: (a) cosmic rays astrophysics, (b) space physics. During the past decades very important theoretical and experimental results were obtain in both directions. They are described in a huge number of publications, monographs, were honored with Lomonosov Prizes.

During the past years the scientisit of the Division obtained the following outstanding results in the field of cosmic rays astrophysics:
1) Cascade theory of high-energy electromagnetic cascades development in different environmental conditions was developed;
2) A prolonged international experiment "Pamir" on the studies of high-energy hadron-nuclear interactions by means of X-ray-emulsion chambers in the mountains resulted in the discovery and anylisys of a new phenomena - coplanar recession of the particles (alignment) during hadron-nuclear interactions of cosmic rays at superhigh energy (over 1016 eV). It was also found that this effect is accompanied by unusually high values of secondary particles' екansverse momentum;
3) International experiment RUNJOB on the studies of nuclear composition of the primary cosmic rays was carried out;
4) Energy of Auger showers was re-evaluated basing on the signals of scintillation detectors of the experimental instruments HiRes and Yakutsk which allowed to adjust intensity of Auger showers in the range of superhigh energy.

Since 2005 the scientists of the Division take part in a significant international experiment OPERA. Its objective is to study oscillations in the flux of muon neutrinos generated on the CERN accelerator (Switzerland) at its spread at the distance of about 730 km under the ground for detection in the underground laboratory Gran Sasso (Italy). During the experiment it was shown that neutrino can change their type. For example, muon neutrino drop into tau neutrino. A group of scientists under the supervision of the Head of the Laboratory Sc.D. Tatiana Roganova directly participate in this research.

Also the scientists of the Division continue the studies of the cosmic rays of superhigh energy (over 1015 eV). These studies are of particular importance for the actual astrophysical problem, because the data on mass composition and anisotropy of cosmic rays can answer the question about the source and mechanism of propagation of primary cosmic rays of such energy. Due to low intensity of superhigh energy cosmic rays flux the only method for their studying is based on registration of Auger showers - plenty of particles, produced by primary cosmic rays during their propagation through the Earth's atmosphere.Themost important method of studies of Auger showers is registration of Cherenkov radiation, generated by fast particles inside detectors or directly in the atmosphere. A scientific group under the leadership of Sc.D. Rem Antonov develops an observational method by means of automatic equipment fixed on the high-altitude baloon. The idea of the experiment consists in gathering light produced by separate Cherenkov flashes of the atmospheric Auger showers reflected from the snow cover under the baloon.

Within the field of space physics the scientists of the Division continue and develop the studies initiated by the founder of this direction Sc.D. Velior Shabansky. Now this research is carried out by the Groups of Professor, Sc.D. Igor Alexeev, Professor, Sc.D. Igor Veselovsky, Sc.D. Alexey Kropotkin. Their studies provide answers for a number of the most important question in the field of space physics on the basis of current theory: non-linear dynmics and theory of self-assembly in dynamical systems, in combination with kinetic theory of collisionless plasma. They allow to understand the reasons of sudden quick alterations in the structure of the Earth's magnetosphere which produce flashes of various activity in the magnetosphere. These flashes - magnetospheric storms and substroms - are very important because in particular they determine so-called "space weather". Clouds of hot plasma and high energy charged particles suddenly appeared near the spacecraft are resulted from storms and substorms.

Detailed studies of the Earth's magnetosphere dynamics during magnetic storms and magnetospheric substorms - the most dramatic and bright phenomena happened in the near Earth space - are based on the analysis of large-scale magnetospheric current systems, thin current layers produced at the border of the magnetosphere, magnetic field structure in the interface behind the detached shock wave.

In 2011 the scientists of the Division Igor Alexeev, Elena Belen'kaya and the Chief of the Department of Space Monitoring Vladimir Kalegaev picked up the First Order Lomonosov Prize. They presented a series of articles at the intersection of astronomy, geophysics and mathematics. The authors developed the models of the magnetic fields of the planets' magnetospheres on the basis of accurate analytic solutions of plasma problems. But at the final stage of comparison with the measurements of magnetic field and during the interactive selection of the inner parameters of the model cumbersome arithmetic is needed to be used. In order to conduct this calculation the authors developed original software. Magnetospheric model appeared to be flexible and corresponding versions are applicable for the majority of the Solar system planets which possess their own magnetic fields - besiades the Earth, they are Mercury, Jupiter and Saturn. Currently the model is succefully used for the studies of the magnetospheres of exoplanets, i.e. discovered celestial bodies which belong to the planetary systems of other stars.

The scietists of the Division have developed the basis of the theory of ion movement in thin plasma sheets and the theory of self-consistent enisotropic kinetic thin current layer based on the existance of a specific adiabatic invariant conforming to the oscillations of the particles during their movement in the layer. Dynamical mechanism of emergy transformation acting during generation of thin layers in space plasma is found and analysed. Its role in the global plasma transformations in space is studied. Developed eory non-linear theory of kinetic thin current layer combined with the results of numericsimulation have shown that the processes of quick alterations of configuration are accompanied by strong effects of transformation from magnetic energy to ion flux energy. For activation of substroms this factor plays a key role. Its comparison with observation data points out that the developed theory explains a wide variety of the effects of quick electron conversion in space plasma.

In the theoretical and experimental studies the scientists of the Division collaborate with a number of RAS institutes (Institute of Space Research (IKI), Lebedev Physical Institute (FIAN), Institute of Nuclear Research (INR)) and develop wide international cooperation: with NASA Hoddard Space Flights Center (Washington, USA), Austrian Space Research Institute (Graz, Austria), Finnish Meteorological Institute (Helsinki, Finland), the Laboratory of Astrophysical and Planetary Studies of the French Scientific Research Center (Tuluse, France), the University of Leicester (Leicester, Great Britain). There are also contacts with other sceintific groups from Sweden, France, Great Britain and the USA. The OPERA experiment on the studies of neutrino oscillations is carried out by a great international collaboration in CERN and Grand Sasso.