NRNU MEPhI

Moscow, Russia

NRNU MEPhI

Moscow, Russia
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Fomin R.V.,NRNU MEPhI | Kolesov V.V.,NRNU MEPhI | Kochnov O.Y.,Karpov Institute of Physical Chemistry
Journal of Physics: Conference Series | Year: 2017

We have studied the possibility of increasing the 99Mo and 131I production through modernization of the VVR-TS reactor core. It has been found in particular that the introducing of beryllium reflector on the core periphery can significantly increase the starting reactivity margin. This, in turn, give us possibility to create an additional channel for increasing their production. © Published under licence by IOP Publishing Ltd.


Garashchuk I.R.,NRNU MEPhI | Kudryashov N.A.,NRNU MEPhI | Sinelshchikov D.I.,NRNU MEPhI
Journal of Physics: Conference Series | Year: 2017

Non-linear dynamical systems describe many physical processes. In this work we investigate a three-dimensional Lorenz-like system - the Glukhovsky-Dolzhansky system. We consider analytical properties of the studied system. The problem of existence of meromorphic solution is discussed. We perform the Painlevè test and find conditions imposed on parameters of the system for which meromorphic solutions exist. Laurent series locally representing solutions are built. First integrals are obtained. We also find simply periodic solutions with one and two poles in a stripe of periods. © Published under licence by IOP Publishing Ltd.


Korneev P.,NRNU MEPhI | D'Humieres E.,French National Center for Scientific Research | Tikhonchuk V.,French National Center for Scientific Research
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2015

A simple setup for the generation of ultra-intense quasistatic magnetic fields, based on the generation of electron currents with a predefined geometry in a curved snail (or 'escargot') target, is proposed and analyzed. Particle-in-cell simulations and qualitative estimates show that gigagauss scale magnetic fields may be obtained with existent laser facilities. The described mechanism of the strong magnetic field generation may be useful in a wide range of applications, from laboratory astrophysics to magnetized inertial confinement fusion schemes. © 2015 American Physical Society.


Korneev P.,NRNU MEPhI | Becker W.,Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy
Laser Physics Letters | Year: 2010

The nonequilibrium nanoplasma created by irradiation of a cluster, or other nanosystems such as large molecules, with an intense infrared-laser field may be used as an amplifying medium for a high-frequency probe field. We employ a simple description where the nanosystem is modeled by particles bound by a self-consitent potential. An incident probe field suffers gain or loss depending on the respective parameters by a mechanism-2 that is usually referred to as collisionless damping. The model is simple enough to allow for an essentially analytical solution. © 2010 by Astro Ltd.


Rashchikov V.I.,NRNU MEPHI
24th Russian Particle Accelerator Conference, RuPAC 2014 | Year: 2014

Computer simulation of deuteron beam from ion source acceleration in gas-filled neutron tube has been fulfilled. Fully relativistic electromagnetic particle-in-cell finite difference, time-domain cod SUMA [1-2] has been used to investigate the ionization and knock on processes and there influence on deuteron beam and output neutron flow parameters. When deuteron and ionized particles space charge self-field forces become the same order of magnitude as external one, virtual cathode may occurs. It is happens because of injected from ion source deuterons cannot overcome their own space charge potential wall and move in transverse direction. However, electrons, produced by ionization, are trapped within the deuteron beam space charge potential wall and decrease it significantly. Thus, space charge neutralization of deuteron beams by electrons, may considerably increase target current and, as a result, output neutron flow. The data obtained were compared with experimental results. © 2014 CC-BY-3.0 and by the respective authors.


Mirnov S.V.,NRNU MEPhI
Plasma Physics and Controlled Fusion | Year: 2016

It was noted earlier [1] that high performance regimes of many tokamaks were achieved in the condition of plasma heating power P H limited from above. The exceeding of this limit usually ended as a plasma collapse. The analysis of the high performance regimes of well known tokamaks which operated during the last 50 years has shown that the values of such 'permissible' P H grow approximately linearly with the area S of the first wall surface facing to the plasma. The paper attempts to explain the existence the P H/S limit for high performance tokamak regimes as a consequence of the vacuum breakdown of the plasma sheath in the area of a plasma contact with the vessel wall and unipolar arcs which followed it. © 2016 IOP Publishing Ltd.


Agafin S.,NRNU MEPhI | Krasnopevtsev A.,NRNU MEPhI
ACM International Conference Proceeding Series | Year: 2014

Most modern cryptographic systems cannot function properly without a reliable random number generator [1-8]. There are many approaches to the construction of the RNGs, but they all have several disadvantages. This paper provides a new approach for constructing truly random number generator, based on non-stability of memory access time. The developers have tried to describe methodology for obtaining and filtering random values from Intel-based systems without additional hardware. Copyright 2014 ACM 978-1-4503-3033-6/14/09 $15.00.


Karelin A.V.,NRNU MEPhI | Borisov S.V.,University of Rome Tor Vergata | Galper A.M.,NRNU MEPhI | Voronov S.A.,NRNU MEPhI
Astrophysics and Space Sciences Transactions | Year: 2011

To date, very little has been done in the field of research of the nuclei cosmic ray spectra in the energy range between 1 and 10 TeV per nucleon and especially there were even fewer direct measurements in space. The PAMELA experiment (Casolini et al., 2008) has a possibility to make progress in this range. The method of the measurement of the helium and proton cosmic ray spectra with the energy higher than 50 GeV/nucleon was developed mainly with the use of the PAMELA calorimeter. This analysis method and the results obtained based on 3 years of measurements are presented. © 2011 Author(s).


Dik A.V.,RAS Lebedev Physical Institute | Ligidov A.Z.,NRNU MEPhI | Dabagov S.B.,RAS Lebedev Physical Institute
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2013

This work is devoted to the electron motion in an infinite plasma-ion channel formed by powerful ultra short laser pulse. Analytical expressions for both transverse energy levels and widths of plasma-ion channeled electrons in simplified approximation of a scalar particle have been derived. The spectra of electromagnetic radiation by channeled electrons in a plasma-ion cavity in the direction of relativistic motion with different initial conditions have been calculated. © 2013 Elsevier B.V. All rights reserved.


Grigoryev E.G.,NRNU MEPhI | Olevsky E.A.,NRNU MEPhI
Ceramic Transactions | Year: 2013

Compressed metal powders have a very large electrical resistance due to the oxide layers on grains. A transition from an insulating to a conducting state of powder sample is observed as the applied current is increased. Experiments show that this transition comes from an electrothermal coupling in the vicinity of the microcontacts between particles where microwelding and electric microexplosion occurs. This paper presents multiscale simulation results of the thermal processes occurring under high voltage consolidation of powder materials. The thermal processes in the contact zones of powder particles are characterized by significant spatial inhomogeneity and time dependence during this sintering. Their analysis and finding of the main regularities in the behavior of the powder material in the contact zones makes it possible to establish the optimal pulse electrical current parameters. The simulation results demonstrate the correlation between the modeling and experimental data for compacted powders of heat-resistant alloy.

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